Mark Ross Pellegrino is an American actor of film and television. He is best known for his work as Lucifer in Supernatural, Paul Bennett in Dexter, Jacob in Lost, James Bishop in Being Human, Clayton Haas in Quantico, Joe Messing in Mulholland Drive, and Deputy Bill Standall in 13 Reasons Why.

Mark Pellegrino was born in Pasadena, California and grew up in Van Nuys, California. He attended Notre Dame High School. When he was in high school, he co-founded and sang in a heavy metal band, XL. It disbanded after school was finished.

Although he enrolled in college and achieved straight As, he dropped out after a year. He saw an advertisement for a modeling agency at a place called John Roberts Powers, where he received some free training. During his training he was picked out for talent by commercial agent Bob Hoover. He was set up with an agent and acting coaches. From there he was sent out into the world of acting and discovered the Meisner acting method. He had no dream to become an actor at the time.

For most of his life, Mark believed Bill Pellegrino (whom his mother divorced when he was two years old) was his biological father. As an adult, Mark ran a search on ancestry.com to learn more about his heritage. He discovered his DNA did not indicate Italian ancestry. Before the COVID-19 pandemic, he asked fans of TV show Supernatural on Twitter (now named X) if they would be interested in finding his real father. Within an hour of posting, his father was found along with the knowledge of having two sisters and three brothers. His biological father, Gerry, is of German descent