Quack has a oval shaped body that is covered with dark blue or a purplish blue feathers that may also change to a light dark blue at night. On the top of his head is a small white sailor hat. Quack has two eyes that are white with black pupils and a black bill is located beneath his eyes. He has two oval shaped black feet that are connected to the rest of his body by his cylindrical black legs.
Quack is portrayed to be bossy and very self centered but also cares for his friends as seen when he helps Chirp tire out Tom, rescuing Peep and Chirp on various occasions, and helping to save his home. He is very attached to his hat and expresses great discomfort when it is gone from his head by force. Quack has a obsession with ducks and likes to eat, sing, and boast about himself.
Quack made his debut in the episode Spring Thing and lives in a pond. Quack is very fanatical about ducks and often sings songs about them and talks about them. He often bosses Peep and Chirp around and argues with Chirp, sometimes falsely accusing her of things that he has done. He is protective of his hat and will sometimes let it be used to carry water, but often grudgingly. Quack has the ability to dive, swim well, and talk underwater and always waddles when he walks. Beaver Boy appears to never refer to Quack by his real name and will either refer to him as blue sailor or, rarely, blue duck.
Peep - Peep is patient and kind with Quack. Even though Quack can brag or show off sometimes, Peep is still kind to him
Chirp - Chirp is friends with Quack but has been shown frequently arguing with him and sometimes challenging what the duck asserts is his or his own accomplishment. Quack in turn will argue back with both birds often going to Peep to help solve their problem. Chirp does not give Quack any ground to boast, whether it be about himself or ducks, but has been seen using it to manipulate Quack such as in the episode Springy Thingy where she, upon asking Quack about whether ducks exceed in certain qualities and gaining his agreement, cause him to let her and Peep stand on his shoulders. Chirp will still help Quack and, as seen in the episode A Duck's Tale, has taken notice of his superior swimming abilities, though not being too fond of the duck trying to teach her how to swim. Quack has on multiple occasions told Chirp how she is a funny bird but this does not appear to bother her.
As Quack in in his pond about to go to sleep, he smells something repulsive, Unable to stay in his pond due to the smell, causes him to rush away half gagging. Quack runs to Peep's can and shouts for Peep to wake up before jumping into his can and ramming into the sleeping chicken. Peep sleepily awakens and asks the duck why he is here causing Quack to being to explain about the smell in his pond only to realize it has disappeared. As Quack beings to explain how terrible the smell was, he falls asleep mid-sentence and later in the morning, he and Peep face the difficulty, and are successful, in get out of Peep's home. Quack tells Peep that he should never ask him to spend the night again and then decides that he will get rid of the smell around his pond. After Peep's inquiry of how Quack will get rid of the smell, the duck responds that he will speak to it sternly which causes Peep to laugh. Quack misinterprets Peeps reaction as doubt and sets out to prove Peep wrong.
Peep tags along with Quack as both go looking for the smell and they stumble across a flower of which Quack, upon sniffing it, deduces it is not the terrible smell. Later Quack finds a sock that, despite its repulsiveness, is also not the smell. Quack then walks away and walks on top of a black and white object and, as he is wondering about the smell, the object moves and looks up at him scaring the duck into jumping off the animal. Quack tells the animal, who happens to be a skunk, off and then asks the skunk if he has smelled anything revolting, whereupon the skunk explains he is the smell. Quack sticks his head in the skunk's tail and comments he does smell something bad but not like the repulsive smell and the skunk explains his defense mechanism of spraying animals with a repugnant odor. Quack attempts to imitate the skunk but the skunk points out that only his kind can do so and Quack angrily walks off. While walking, Peep asks Quack if he finds that flower that they saw was beautiful and Quack tells Peep to forget the flower and instead expresses his awe at the skunk's ability. A bee happens to drift by and Quack tells of the skunk's ability to the bee who, being unimpressed, tells Quack of its ability to sting others before flying away. Quack asks Peep if he can find a stinger on him but Peep does not but instead finds a small feather.
Quack sighs and walks off while stating some of the abilities he lacks when suddenly, a porcupine hits a tree with its quills scaring both birds, but later apologizes. Quack asks the porcupine about his quills and the porcupine explains how it uses his quills to defend himself before walking off. Quack gestures to Peep to see if he has quills but Peep does not find any. Quack then laments about his lack of abilities and belittles his being a duck with finally going back to his pond to mope. While floating around aimlessly in his pond, Quack hears a voice call out to him and it is revealed to be a very disheveled Chirp. Quack informs her mournfully that she will have to come back another time. Chirp tells Quack she has been looking for him everywhere and jumps onto him and explains that Tom has been chasing her and she needs his help. Quack, still in low spirits, says that he is the wrong person as he has found out that ducks are unable to get rid of things. Tom suddenly appears and swipes at Chirp but Quack moves out of the way. Chirp then happily tells Quack that what he did was what she wanted. Quack does not understand and states, while swimming away from Tom's claws, that he is trying to get away from the cat and Chirp agrees and points out his incredible swimming abilities. Quack then remembers how ducks are good at swimming and, with his depression broken, begins to taunt Tom as he evades the cat's attacks. Tom eventually becomes tired and leaves and the two birds rejoice and Quack lets Chirp onto the shore. Chirp praises Quack and the duck mentions that she could say that he is the best swimmer she knows and asks her to say it. Chirp rolls her eyes and then points out the differences in size between their feet allowing Quack to swim better. The two birds compare feet and Quack then says they're the biggest, fastest feet in the world. After thanking Quack again, Chirp leaves and Quack swims over to the skunk, who is drinking at his pond, and tells him not to make smells at his pond or he'll swim away. Quack is last seen swimming around his pond and singing about ducks.
The episode starts out by showing a light blue sky with a visible sun , a few trees in the distance, snowy ground, a partly snow covered bush, and a partly snow covered log. The camera pans to the left and zooms up to Peep's can, showing Peep sleeping and then awaking to find the world covered in fresh snow. Peep runs to tell Quackabout the snow and finds Quack asleep with snow on his face. After the duck gets out of the pond and warms up, Peep asks if he wants to come and build a snow chick, whereupon Quack agrees and suggests it be built on snow hill.
Peep lets Quack lead and Quack suggest a snow duck be built instead of a snow chick. As the two are walking, Peep accidentally trips in a foot print in the snow while Quack, oblivious to this, heads off in the other direction while voicing his plans. While Peep observes the footprint, Chirp comes along and startles Peep by suddenly speaking. Chirp asks Peep if he lost something in the footprints and, seeing the chicken's confusion, explains what they are and how to make them. The two being to play and, while playing, Peep notices that the foot print he had tripped in are different from his. Upon Chirp's suggestion, the two birds follow the footprints to find the animal the made them. The path eventually leads to a log where the two discover and have a surprise meeting with the maker of the prints: Tom the cat.
Tom begins to pace around the bird and make them uneasy, but Chirp tricks Tom into believing a spider is on his tail and the two birds quickly escape. Chirp asks Peep what started them accidentally meeting Tom and Peep tells Chirp that he was going to make a snow chick with Quack. Peep realizes he has lost Quack and Chirp suggests they find Quack's tracks and follows them. After Peep determines which tracks are Quack's, he thanks her and begins to follow them, eventually finding Quack rolling a snowball up snow hill. After Peep explains how he found Quack, much to the duck's disinterest, he begins to help him make a snow duck per his request. When the snow duck is completed, Peep shows Quack how to make a footprint path so that others can find it with the episode ending with the two looking at it from the bottom of snow hill.
Quack first appears near the start of the episode sleeping in his pond. Quack awakens the next morning and stretches, yawns, and gargles water before scratching himself and getting out of his pond. While on the shore, the duck squats up and down a few times, wiggles his toes, then looks briefly at his reflection and remarks positively on it. Having finished his morning routine, Quack heads off happily, looks down briefly and remarks on the quality of his feet, before suddenly bumping absentmindedly into a rock. Having fallen backwards due to the collision, the duck rises up, somewhat dazed, before observing the rock and pointing out to it that it is on his path. Quack rephrases what he says and ends his statement with an angry exclamation for it to move. The rock does not reply nor move, and thus Quack leans forward and glares at it before walking back down the hill and muttering angrily to himself.
Quack is then seen from ground level with his head under the water of his pond talking, in presumed annoyance, to its residence. After hearing Peep call out for him wondering if he is at his pond, the duck reemerges and, in annoyed tone, emphasizes the fact that he is there while slipping in a mention of the rock. Quack then asks Peep if he happened to see it and Peep asks if it was "big and round". Quack agrees excitedly and then tells Peep of his experience with it mentioning how it got in his way. Peep tells how the rock didn't get in his way whereupon Quack gets out of the pond, states how the rock may not block the way up but does block the way down, and finishes by stating that he will never be able to visit Peep again until it moves. Peep goes behind Quack and starts to nudge him forward with the narrator explaining the Peep has persuaded Quack to move the rock just as the duck arrives near it. Quack then states how the rock "won't listen to reason" and Peep mentions how he thinks the rock needs to be pushed as it is unable to move on its own, which surprises the duck. Peep tries several attempts to move the rock but is unsuccessful and begins to head far up the hill. Quack concludes that Peep is leaving him for eternity and speaks mournfully about how he doubted the rock would break their friendship, whereupon the chicken turns around at the top of the hill and states how he is not giving up.
Peep runs down the hill quickly and ends up on top of the rock where, from his vantage point, he mentions being able to see Nellie's doghouse. Distracted by this, Quack excitedly asks if Peep can see another location but suddenly catches himself and states that he is only concerned with moving the rock. Suddenly Chirp happens along and, after Peep informs her what they are doing, inquires why they are trying to move the rock. Quack then states that it is blocking his path and Chirp, after peering around the rock, suggests Quack simply moves around it. Quack finds this unbelievable and then attempts to clarify by pointing out to Chirp the path and then the rock. Chirp and Peep head off to get help while Quack stands behind the rock in a stubborn pose. Quack is then seen observing the animals Peep and Chirp have gathered push the rock sideways before turning to the camera with an expression of worriment and annoyance.
As the animals are speculating on pushing the rock down the hill, Quack rushes towards them and stands on top of the rock. The duck then voices his desire to keep the rock away from his pond and, after looking around, directs the animals to push it against a tree next to his pond. With the animals in agreement, they begin to push against the rock with Quack on top of it and Quack notices it is moving and points this out. After directing the animals to push harder, the rock dislodges and begins to roll with Quack unfortunately on top of it. The duck struggles to keep his place and screams as well as calls out for the rock to not move as fast. The rock suddenly hits a smaller stone and sends the duck flying into the air to eventually land on the ground, appear somewhat dazed, and then be left soaking after being splashed by water from his pond. Quack is then seen looking at the rock in his pond mournfully and, as the time passes, is told to get on more amiably with it. Quack is last seen going up to the rock and scratching himself against it, sighing in relief, before swimming away in satisfaction.
Peep in Rabbitland - Quack is shown at the start of the episode walking with Peep on a late afternoon in a somewhat forested area. Quack informs Peep that if he follows in his footsteps nothing will ever go wrong and jumps over some objects in his path while talking. As Quack is in front, he doesn't notice Peep fall downwards into a hole but, after becoming suspicious, he turns around and notices Peep is missing. Quack calls out to Peep and finally yells down into the hole he fell into but his voice becomes muffled to his friend below. Quack becomes angry and continues to yell down into the hole. After much time passes, and Peep finally emerges from the hole he fell into, he finds Quack sleeping nearby. Quack awakes and asks where Peep has been to only later cut Peep short and complain of his disappearance being inconsiderate. Peep apologizes and Quack accepts it and Quack is last seen walking back with Peep as the chicken remarks about the world.
Newton's Big Adventure - Quack is seen near the start of the episode running to Newton's tree with Peep to see Newton. Quack tells Newton how he got stuck in a hollow log and Peep asks Newton what he did. Newton tells that an apple fell on him and another did with on the third time Quack interrupts Newton in impatiences to correctly state that an apple fell on him. Peep then suggests that Newton should come have adventures with them and Quack appear in obvious discomfort. Newton then states that he is not as fast as them and Quack, seizing this opportunity, hastily agrees and steers Peep away from Newton and down the hill. Quack is later seen at the end of the episode, in the evening and with Peep, walking by Newton's tree and remarking how the turtle is still sleeping and has not moved. Quack is last seen walking away from the tree to leave Newton to rest.
Quack will jump onto the paint tubes the player clicks on in Paint Splat and will often say a short sentence when doing so. When the player clicks on the hose, Quack will yell, "Hose!" and jump out of the way.
Quack has been shown eating seeds even though he posses no visible teeth.
Oddly, when Quack goes underwater and begins to talk, after a certain amount of time he must go back up to get air even though he shouldn't need it for if he did he wouldn't be able to talk underwater.
In Quack and the Very Big Rock, one scene near the end depicts Quack becoming drenched in water. This is unusual as Quack is never seen in a such state after diving into his pond and then exiting.
Quack and Peep are the only two characters to appear in every episode.
Quack cries in 11 episodes: Peep Crosses The Road; There's No Place Like Home; Mirror, Mirror, In The Dump; Quack Hatches An Egg; Finders Keepers; Chirp Sort It Out (Sort Of); Dry Duck, Part 1; One Duck Too Many; Nosing Around; You Can Count On Bunnies; and Soap Opera.