Sebastian Siegel is a British-American screenwriter, director, author, and actor from Oxford, England. His father is Indian religions professor and widely acclaimed writer, Lee Siegel. His grandfather, Leonard Thompson, was an active opponent of apartheid, author, and professor of South African history at Yale. Sebastian began studying drama at age seven. He was accepted to college at age fifteen to study theatre, and won the drama prize at Kent School.

He often credits gratefulness to theatre, zen, rigorous exercise, authors Alan Watts, Ken Wilber, James Hollis, other philosophers and artists, and friend and mentor James Whitmore.