Lipnicki made his film debut in Jerry Maguire as the son of Renée Zellweger's character. He subsequently appeared on The Single Guy, The Jeff Foxworthy Show as well as episodes of Dawson's Creek and the 1997 sitcom Meego. In 1999, he starred in the film Stuart Little, playing a boy whose family adopts a talking mouse, a role he reprised in the film's 2002 sequel. He also played the lead, Tony Thompson, in the 2000 film The Little Vampire and starred opposite Bow Wow in the 2002 film Like Mike, which was released two weeks before Stuart Little 2. The latter films did relatively well in theaters, and Lipnicki has become known among pre-teen audiences, although he has not appeared in a widely released film since, focusing mostly on independent films. Lipnicki has also appeared in the season preview of Jamie Kennedy's Blowin' Up and When Zachary Beaver Came to Town. He appeared on the comedy Motherlover on the YOMYOMF Network.