James Gunn

James Francis Gunn Jr. was born on August 5, 1966 in St. Louis, Missouri, to parents James F. Gunn, an attorney, and Leota "Lee" (Hynek). He was raised Catholic in the St Louis suburb municipality of Manchester, Missouri. He has five siblings — actor Sean, actor and political writer Matt, screenwriter Brian, Patrick, and Beth. Gunn is of Irish and Jewish descent his father coming from an Irish immigrant family. Gunn has stated that his family's surname was originally the Irish name MacGilgunn and that it means "sons to the servants of the god of the dead"; it actually means "son of the brown youth."

Growing up, Gunn was influenced by low-budget films such as Night of the Living Dead and Friday the 13th. He read magazines like Fangoria and attended genre movie screenings, including the original Dawn of the Dead at the Tivoli Theatre in St. Louis. At the age of 12, he began making 8 mm zombie films with his brothers in the woods near their home.

Gunn and his brothers all attended the Jesuit St. Louis University High School, where he graduated in 1984. He went on to earn a Bachelor of Arts from Saint Louis University. While at Saint Louis University, Gunn created political cartoons for the school's student weekly, The University News. Gunn said that, at an unspecified time in his college education, "I went to two years undergraduate film school at Loyola Marymount in Los Angeles. But I was pretty screwed up at the time, and had to leave. Years later I went to graduate school at the Columbia University School of Fine Arts but I studied prose writing, not film writing." He earned a Master of Fine Arts from Columbia University in 1995.