In the film, he behaves as if he is constantly nerve-wracked and completely delirious. He is a cook in the film as well, and the way he eccentrically throws dishes and pots suggests he is an amalgam of both the March Hare and the cook from Lewis Carroll's original book. Thackery has a strong Scottish accent in the film, while his friend Tarrant Hightopp:switches into a Scottish accent whenever his emotions are strained.
Thackery is first seen in the "Tea Party" scene, which takes place at his "Hare House" windmill. He hosts a tea party, which he shares with Tarrant Highttop, Mally, and Chessur. When Alice arrives, Thackery participates in the conversation with Chessur and Mally to which the conversation becomes interrupted when the Knave of Hearts and an army of Armored Cards arrive, just as Thackery drinks his tea nervously. As the Knave arrives, Thackery offers him some cream to which the Knave doesn't respond. Thackery and Mally later stay together in the tea party while Tarrant takes Alice to the White Queen.
He then appears a second time in the White Queen's kitchen, frantically cooking and throwing dishes. Furthermore, he appears again at the Frabjous Day scene, in which he stands with the other characters wielding a ladle as his weapon, nervous and somewhat ready to go to battle (which Tim Burton stated that because Whitehouse is a great comedic actor, a lot of his lines came from improvisation). Fortunately, the battle stops when Alice slays the Jabberwocky. Following the arrests of the Red Queen and the Knave of Hearts, Thackery and the rest of Alice's friends watch Alice return to the real world.
In the video game adaptation, Thackery is a playable character. His special ability is telekinesis, and his main form of attack is to throw teacups. He also uses his big feet and large ears as weapons.