L. Marcus Williams was born in 1975, in the suburbs of Long Island, New York. As a child, he was inspired by his father's love for classic cinema and his mother's success as a director of community theater. For fun, he would make movies with his friends in the backyard, using the family's home video camera.

In 2002, he wrote and directed his first feature-length film, "written by Franklin Mann," about a novelist struggling with writer's block and sexual repression. It was made in accordance with the Dogme 95 Manifesto. He followed that with "Scopophilia," in which he also starred as a man with an unhealthy obsession over his dead sister. The film premiered in 2003, at the Three Rivers Arts Festival in Pittsburgh, Pennsylvania.

In 2005, Williams moved to New York City where he earned some modest success as a freelance director for the stage. His one-act play, "Role Play," won the Audience Favorite Award at the Short Play Lab in 2011. In 2012, he directed Daniel Guyton's "Attic" for the Midtown International Theatre Festival and an Off-Off-Broadway production of Neil LaBute's "reasons to be pretty."

Williams returned to the world of filmmaking in 2015, when he enrolled in the film degree program at Brooklyn College. His first two student films, "The Monster Under My Bed" and "Nail-Biter," were both released in 2017. The latter, about a desperately lonely man who breaks into a woman's apartment just to feel close to her, premiered on Amazon Video.

His thesis film, "Lifeline," was released in 2018. Based on his own experience as both a volunteer crisis hotline operator and a survivor of attempted suicide, it was voted by the faculty as the top thesis film of the school year, and Williams won Best Director and Best Editor Awards at the Brooklyn College Film Festival. Additionally, the film earned Williams a Student Grant from the National Board of Review and was nominated for Best Short Film of the Year by the critics at UK Film Review.

Williams is currently developing a feature-length film about a suburban family who discover that one of their own is a suspected serial killer. He lives in Brooklyn, New York, with his wife and son.