Garner Simmons has been a member of the Writers Guild of America since 1978. He received his BA from Colgate University (English/Fine Arts) before becoming what his father liked to call "the best-educated bartender in Chicago." He served in the US Army National Guard on the streets of Chicago during the riots surrounding the assassination of Martin Luther King Jr., the 1968 Democratic Convention, and Kent State among others.

A graduate of Northwestern University's School of Communication in Radio/TV/Film, he is an internationally recognized authority on the life and films of the late Sam Peckinpah. He has spoken at various festivals and retrospectives of Peckinpah's work including Bologna, Italy (2006), the Locarno (Switzerland) International Film Festival (2015) and New York's Lincoln Center (2016).

A member of the Directors Guild of America, the Academy of Television Arts & Sciences, and of the Writers Guild of Canada, he is a multiple-winner of the WGA Feature Writer Access Competition (2015, 2016). As a member of the Dog Brothers, he has done the audio commentary on all of the DVDs of Peckinpah's films except Cross of Iron and Deadly Companions (both unavailable due to rights issues). A member of the Sisyphean School of screenwriting, he lives with his wife, educator Sheila McHugh Simmons, in Los Angeles, California, where he has recently completed his first novel.