He was born in Montreal, Quebec in 1969, the youngest of four children of Chinese immigrants and grew up in Scarborough, Ontario, a suburb of Toronto. He graduated with honours from the animation program at Sheridan College in Oakville, Ontario. He worked on television cartoons and commercials for several studios, including Kennedy Cartoons in Toronto and Colossal Pictures in San Francisco before joining Pixar in June 1996.
In August 2003, he was diagnosed with lung cancer, despite the fact that he was a nonsmoker. He died in 2005 at the age of 35 in Alta Bates Summit Hospital, Berkeley, California, USA. The 2007Pixar movie Ratatouille was dedicated to Lee.