Mark Anthony McDermott was born in Waterbury, Connecticut, the son of Diane and Richard McDermott. His father was of Irish descent, and his mother had Italian and English ancestry. His mother was fifteen and his father was seventeen when he was born. He has a younger sister, Robin. By 1967, the couple had divorced, and Diane and her two children were living with her mother. On February 9, 1967, his mother was shot dead. Her death was originally ruled an accident. Police later claimed that evidence they found would be enough to file murder charges against John Sponza, who had been living with Diane McDermott at the time. Sponza had told authorities that she accidentally shot herself after picking up a gun he had been cleaning. Sponza, who police say had ties to organized crime, was shot dead in 1972, his body found in the trunk of a car in a Waltham, Massachusetts, grocery store parking lot. Dylan was 5-years-old when his mother died. He and his sister were raised by their maternal grandmother, Avis (Rogers) Marino, in Waterbury.

As a teenager, McDermott began taking trips to visit his father, who owned the West Fourth Street Saloon in Greenwich Village. The two would go to the movies and the younger McDermott would work in his father’s bar serving drinks and breaking up fights. He would also fast talk his way into the Mudd Club and Studio 54. McDermott was uncomfortable with himself as a teenager, saying he had a “Dorothy Hamill hairdo”. He began to imitate his acting heroes, such as Marlon Brando and Humphrey Bogart, to adopt their demeanor. McDermott graduated from Holy Cross High School, Waterbury.

His father’s third wife was playwright Eve Ensler (author of The Vagina Monologues), who legally adopted McDermott when he was 15 and she was 23; she has since divorced his father. Ensler, with whom he has remained close, encouraged McDermott to pursue an acting career[3] and began writing roles for him into her plays.[1] After Ensler suffered a miscarriage, he took on the name Dylan — the name planned for her unborn child. He attended acting school at the Jesuit-run Fordham University, as well as studying under Sanford Meisner at the Neighborhood Playhouse.

taken from Wikipedia