Piglet's Big Movie suggests that Roo and his mother Kanga are the newest residents of the Hundred Acre Wood. He and his mother live in a tree house where they have a conjoined mailbox. Roo is, unsurprisingly, the youngest member of Winnie the Pooh's circle of friends. The earliest Pooh shorts, such as Winnie the Pooh and the Blustery Day and Winnie the Pooh and Tigger Too, portray Roo as a toddler that spends most of his time tucked inside his mother's pouch. The earlier shorts also depict Roo as still learning to speak, as he was unable to pronounce Christopher Robin's name. More modern Pooh media depict Roo as slightly older and more proactive. He rarely spends time in his mother's pouch and will often take part in the shenanigans of Pooh and friends without Kanga's involvement.
Roo's youthful and energetic personality (as well as his natural love of bouncing) makes him the perfect companion for Tigger, with whom Roo shares a relationship akin to two siblings. However, his young age sometimes prevents him from tagging along on Pooh's adventures (mainly because Rabbit and even Tigger believes Roo's too young for certain expeditions). When not with Tigger or Kanga, Roo spends his free time with Dexter, Owl's cousin. Since Lumpy's introduction, he and Roo have been portrayed as best friends and spend most of their time together.
Roo takes after Tigger in that he is spirited and adventurous. He acts his age, being curious and energetic. He is also optimistic and fearless; when he and Tigger were stuck atop a tall tree, Roo remained calm and upbeat throughout the entire ordeal while Tigger was petrified. Another example is the time Roo was caught in a river. Rather than panicking, he remained happy-go-lucky, despite how worried the adults were. His fearlessness also drives him to be daring and even a little rebellious. Roo was the most excited to catch a Heffalump in Pooh's Heffalump Movie and scoffed at the idea that such a mission would be too dangerous for him to handle. When Rabbit forbade him for tagging along, Roo ventured into Heffalump Hallow anyway.
Roo is rather wise for his age, at times. He was initially afraid of Heffalumps due to the legends he had heard from the adults around him but was open to the prospect of a Heffalump being just as harmless and friendly as the Hundred Acre Woods residents. Roo was, in fact, the first member of the Hundred Acre Woods to befriend a Heffalump, which kickstarted a mutual understanding between Heffalumps and the Hundred Acre Woods gang.
Roo is a joey whose height is similar to Piglet's. Roo has light brown fur and an upturned tail. He has beady black eyes and thin eyebrows. He also has a small nose and black mouth. His only attire is a sky blue long-sleeved T-shirt that he wears all the time. Finally, Roo sports two strands of black hair on the top of his head. The inside of his ears is light pink and he has pink pads on the bottoms of his feet.
Roo makes minor appearances in the first two segments of the film. In Winnie the Pooh and the Honey Tree, he is first seen with his mother Kanga, as they are watching Christopher Robin fix Eeyore's tail. Roo is delighted when the tail is fixed properly. Later on, he assists in Pooh's removal from Rabbit's door, at the very end of the line pulling Eeyore's tail, but accidentally ends up pulling it off, when Gopher comes along to help Roo.
In Winnie the Pooh and the Blustery Day, Roo is seen momentarily with Kanga. They both see Piglet being blown like a kite by the wind, with Pooh holding on to Piglet by his unraveled scarf. Roo asks to fly Piglet after Pooh is finished. During the flood, Roo travels to Christopher Robin's house with Kanga and Tigger. There, Roo is the one to discover the bottle containing Piglet's message.
Roo has a larger role in the third segment, Winnie the Pooh and Tigger Too. During wintertime, Roo goes to play in the snow with Tigger. At one point, Tigger and Roo bounce up a tree. Unfortunately, Tigger discovers his fear of heights and remains trapped. Christopher Robin, Kanga, and other animals come to the aid of the pair. Roo jumps down and lands on Christopher Robin's coat, which they were using as a net. But Tigger is only about to come down with some assistance from the narrator, after which Tigger promises never to bounce again. On the ground, Rabbit holds Tigger to his promise but reneges after Roo notes how much he likes the bouncy Tigger.
Roo first appears playing Pooh Sticks with Pooh, Piglet, and Rabbit. They find Eeyore drifting away in the river, but are able to save him. When Tigger is accused of bouncing Eeyore into the water, Roo doesn't pay it much thought, only hoping to play with Tigger. Later on, Roo is present at Eeyore's birthday party, and lastly during the Pooh Sticks game with all the Hundred Acre Wood gang. When Kanga tells Roo that it is time to go home, the latter tries to protest by claiming he is not sleepy (while yawning as he does).
In this film as the deuteragonist, Tigger longs to find his relatives and Roo decides to join him on his search. At Tigger's tree house, the duo uncovers a locket that Tigger believes was given to one of his family members. With high hopes, Tigger and Roo send a letter inviting the other Tiggers to a family reunion in the Hundred Acre Woods. Soon enough, the letter is never replied to and Roo heads home. That night, Roo tells his mother of the event and they decide to write a family oriented letter to Tigger. When he received the letter, Tigger thought it was from his actual family and becomes overjoyed after believing they are making their way for a visit. Roo and the others then pose themselves as Tiggers but the charade is revealed when Roo attempts to perform the famous Whoop-de-Dooper Loop-de-Looper Alley-Ooper Bounce. Heartbroken, Tigger leaves the Hundred Acre Woods to find his relatives. Roo, Pooh, Piglet, Rabbit, and Eeyore set off in a blizzard to find Tigger and bring him home. After an avalanche, Christopher Robin explains that Roo and the others are Tigger's real family. Tigger is pleased with the realization and even deems Roo his little brother, giving him the Tigger family locket as a gift.
In this film, Piglet leaves the Hundred Acre Woods, feeling out of place because of his diminutive size. Roo and the others then head out to find him, using the pictures in Piglet's scrapbook as a map. While searching, each picture brings a fond memory that reminds the friends of how heroic Piglet is. One memory goes back to when Roo was being dragged away by a river, only to be saved by Piglet, though Pooh was the one that received the credit. At one point during the search, Tigger and Rabbit engage in an argument, resulting in the book being dropped into the river and drifted away. Roo and the others head back home for a moment but become inspired to run back out to try again. Pooh spots the book on the log over a waterfall and attempts to retrieve it. The bear nearly falls until Piglet arrives. The friends reunite, and Piglet is deemed a hero.
Roo is the main protagonist in this film. Here, Rabbit, Tigger, Piglet, Pooh, and Eeyore head off on the very first Heffalump Expedition. However, Roo is excluded because he is too young. After the gang heads off into Heffalump Hollow, Roo decides to head in to catch a Heffalump himself, proving to be a hero. Instead, he meets and befriends a young Heffalump named Lumpy. The two become very close but Lumpy is soon enough ambushed by Tigger, Rabbit, Piglet, and Pooh, who think Roo is being attacked. Lumpy gets caught in a Heffalump trap but Roo frees him. Lumpy then departs the scene but Roo ends up trapped in a thicket made of trees. Lumpy quickly calls his mother for help and the large Heffalump succeeds to vacuum up Roo with her trunk. Thanks to the friendship of Lumpy and Roo, the Heffalumps make peace with Pooh and the others.
Roo stars in his own movie as the central protagonist. In the film, Roo, along with his friends is excited about Easter, which is fast approaching. However, Rabbit has decided to replace the day with Spring Cleaning Day, which he made up. While cleaning Rabbit's home, Roo finds Easter decorations and throws a surprise Easter Party, but Rabbit is upset. Roo resolves to try to cheer Rabbit up. Later on, they learn from Tigger, who had spoken with Rabbit, that Rabbit had become upset after last year's celebration. When the friends wanted a fun Easter, rather than the orderly one Rabbit had planned, they had chosen Tigger to be the Easter Bunny over Rabbit. Roo wants Rabbit to be happy, and so he and the others try to make a plan to cheer Rabbit up. They begin to work, when Rabbit comes in, having had a change of heart, and Easter goes on as planned. In the film, he acted as Tiny Tim from The Christmas Carol.
Roo plays a supporting role in the newest feature. He is more often seen in his mother's pouch. He was first seen with his mother, receiving a message from Pooh about an important meeting to take place. There, Roo and his friends learn that Eeyore's tail is missing and a prize is to be distributed to the one that can find it, or a substitute. Roo suggests a firecracker as the prize but the rest of the gang decide on honey. At Owl's house, Owl tries to interpret a note left by Christopher Robin and Roo openly questions the fact if Owl can or not. Eventually, Owl deduces that Christopher Robin was kidnapped by a creature called the Backson. The others are curious to know what the beast looks like, and Roo provides some chalk for Owl to draw it. Roo and his mother join the rest of the gang on an expedition hunt for the beast. Roo uses his crayons and toys as bait to lure the creature into a deep pit. Later on, something is caught in the pit and Rabbit, Kanga, and Owl argues about who should check until Roo suggests Piglet. It is revealed that Pooh is trapped, and soon enough, the rest of the gang is as well. Once they escape, Christopher Robin appears, explaining that he was only at school. When Pooh finally finds Eeyore's actual tail, Roo and the others reward him with an oversized jar of honey.
In this series, Roo was represented by a standard puppet, unlike the other characters who were played by humans in adult-sized puppet costumes. In early episodes, Roo is a toddler and is usually seen either in Kanga's pouch, a high chair or on the back of Eeyore or Tigger. In later episodes, he appears to be preschool age and walked around more. He shares a song with Tigger called "Be a Buddy, Be a Pal".
Roo is a secondary character in the animated series. He features prominently in the episodes "The Old Switcheroo" and "The Bug Stops Here". In "The Old Switcheroo", Roo is trying to avoid a bath, so Tigger switches him with Piglet. However, Kanga believes that Roo is merely acting like Piglet. In "The Bug Stops Here", Roo, along with Owl's young Cousin Dexter, is being babysat by Pooh. Pooh takes the pair to see Christopher Robin, who shows them his science project, a bug. When the bug disappears, Roo must help Pooh and Dexter find a new bug.
Roo is a semi-regular character and featured in a number of stories. In one installment, he makes up his own dance, "The Roo", featured in the song "Do the Roo". In another story, he is sick in bed and dreams of being a cowboy in the song "Call Me Buck-a-Roo".
Roo plays a supporting role in the series, often seen alongside Lumpy. Together, Lumpy and Roo often partake in their own adventures and occasionally joins the Super Sleuths in their mysteries. One installment, "How to Say I Love Roo" focuses on Roo trying to find an "I Love You Day" gift for his mom, Kanga. In another installment, "Roo's Pebble in the Pond", Roo learns that even small acts of kindness can have a big effect.
Roo appears in many of the mini-games in the 100 Acre Wood. The games he shows up in are Tigger's Giant Pot, Pooh's Muddy Path, Balloon Bounce, and The Exposition. In Kingdom Hearts, he is a big help in the Bouncing Spot page area where he helps Sora by catapulting him into the trees to get special items or Rare Nuts for Owl and he helps Sora by giving advice with Tigger's challenges.
In Kingdom Hearts, Roo is one of Pooh's friends that he is looking for.
Roo makes rare appearances in the Disney theme parks, inside the pouch of his mother. The character is almost exclusive to parades, though a walkaround version has appeared in Disney Live! productions.