Jock is the tritagonist in Lady and the Tramp, and a supporting character in the sequel. He is a friendly but sometimes grumpy Scottish Terrier and one of Lady's neighbors. At the end of the first film, he also becomes Tramp's friend and the honorary uncle of his and Lady's puppies.
Although sweet and loyal, Jock can be the most aggressive dog in Lady's circle of friends, in spite of being the smallest. Nevertheless, he values his loved ones and makes an effort to make such a fact clear, on a consistent basis.
He treats Lady as his own relative, watching her grow alongside Trusty and continuously congratulates the spaniel on her many accomplishments, such as the day she received her first collar. He also takes it upon himself to mentor the young pooch, teaching her the ways of welcoming a new baby into the household, and telling her stories of Trusty's past and such.
He is notably the best friend of his neighbor, Trusty who, like Lady, he treats like a relative, along the lines of a brother. The two get along fine, but with Trusty's bumbling ways and Jock's occasional aggression, they sometimes clash, though they never let it tamper their friendship for long, if at all.
As seen in the film, some of Jock's dislikes includes the exposure of his prized bones, Trusty's clumsiness and "mongrels" like the Tramp.
In spite of his size, Jock is a fearless protector, and will go to great lengths to protect the ones he care about. Three instances of this can be seen, where he threatens to attack Tramp, a dog twice his size, if he continues to "harass" Lady, and lastly when he risks his life to stop the dogcatcher's wagon from taking Tramp to the pound, as a way of repaying the mutt for mistreating him early on in the film; showing he's an honorable dog that isn't afraid to admit mistakes.
Lady and the Tramp
Jock first appears while singing Jock's Song as he buries his bone in his secret spot. Jock is then encountered by Lady who presents her brand new collar complete with a license. They then go to visit a dreaming Trusty. As Trusty dreams, Jock confesses to Lady that unfortunately Trusty has lost his sense of smell. The next day Jock along with Trusty visits Lady as it is a perfect day until Lady tells them "bad news." She tells the duo that Darling has not been treating her the same along with Jim Dear.
Jock and Trusty quickly realize what's going on and as Jock puts it, "Darling is expecting a wee bairn." They start to describe what a baby is until Tramp arrives. Tramp shoves Jock out of the way to speak to Lady which upsets Jock. Jock barks at him to keep away from Lady. Jock later reappears near the end of the film after Lady and Tramp got to know each other. At this point, Lady cannot stand him, and when Tramp returns after being separated by the Dogcather , Jock is prepared to attack when ready although Lady claims it's alright. After Tramp redeems himself by killing the attacking Rat, Jock along with Trusty has seen that Tramp is not all that bad of a dog. Jock felt extremely stupid and ashamed for misjudging Tramp badly.
Jock and Trusty rush to the dogcatcher's vehicle and attempt to stop it. Although they do, Trusty is apparently killed in the crash. Jock attempts to help but it seems there is no use. Jock then howls and mourns for his seemingly departed friend. That Christmas, Jock joins Lady along with her husband Tramp and four puppies. Despite Scamp, Lady's only son, tearing up his plaid sweater, he remains calm and congratulates Lady and Tramp on their kids, also noting Tramp's collar. As for Trusty, it seems he survived the crash with a broken leg and attends the Christmas celebration as well.
One Hundred and One Dalmatains
Jock makes a cameo appearance in the classic film. He is among the first of the dogs to pick up the Great Dane's barks during "The Twilight Bark" sequence. He then sends the message up to a drain pipe.
101 Dalmatains The Series
Jock makes another cameo in the spin-off TV series in the pilot episode, "Home is Where the Bark Is".When Lucky asks Jock for a ride in his human's boat, after they miss the ferry, he at first turns them down before realizing that they are the Puppies that Pongo and Perdita sent out a barking chain message about. He is then all too happy to use to boat to help the pups cross the water (his human is asleep during this sequence).
Later, as the pups race Cruella back to the Dearly Farm Rolly frets that there is no way they can outrun Cruella's Car. Jock then tells the pups to get going as he sends out another barking message to the farm animals so they can set up traps to delay Cruella. In the series, he is shown to wear a red sweater.
101 Dalmatians II: Patch's London Adventure
In the film's sequel, Jock appears as the first of the dogs auditioning for the heroic bark contest with Thunderbolt
Lady and the Tramp II: Scamp's Adventure
in the Fourth of July celebration at the beginning, he appears in the beginning where he watches Scamp being wild with Trusty. The evening after Scamp ran away, Jock goes with Lady, Trusty and Tramp, but they only find a wig and leave. Jock and Trusty eventually find Scamp and join his family in welcoming Angel into the family.
House of Mouse
Jock makes a handful of cameos in House of Mouse Jock's most notable appearance is in "Pluto Saves the Day", where he joins an all-dog band singing "Everybody wants to be a woof" Later in that same episode, he is seen with the other Pet Shop Dogs fighting off Pete (who's disguised as Snow White) and then chasing him out along with the rest of the dogs and Pluto.
Oliver & Company
Jock makes a brief cameo in the film Oliver & Company along with Trusty and Peg during Doger's musical number "Why Should I Be Worried"
Phineas and Ferb
Jock also makes a few cameos in His most notable appearances are in "Got Game", "Interview with a Platypus" and Tip of the Day.