Although he plays A-list movie star Vince Chase on Entourage, Grenier needed this TV role to become a bona fide celebrity. In the late '90s, his quirky persona and trademark five o'clock shadow were featured in a number of films---including The Adventures of Sebastian Cole, Drive Me Crazy, Cecil B. DeMented and the Woody Allen films Celebrity and Anything Else---but Entourage proved that the endearingly scruffy actor could clean up quite nicely and be compelling to boot. Off-camera, Grenier is delightfully offbeat. As a musician, he plays percussion in the "Appalachian glamrock" outfit the Honey Brothers (performing under the pseudonym Honey DuContra) and he also appeared as lead singer of the band Kid Friendly. A burgeoning behind-the-camera career found him directing the 2002 documentary A Shot in the Dark, about his real-life search for his estranged father, with whom he later developed a warm relationship. He also directed the 2006 black-comedy short Euthanasia before producing and hosting the green-themed TV series Alter Eco, an undertaking that tapped into his eco-friendly sensibility.
- Is of Apache Native American and European descent.
- Made his feature debut in the independent film Arresting Gena (1997).
- Has his own production company, Reckless Productions, and has written and directed some film shorts and a documentary.
- Played a member of the entourage surrounding Leonardo DiCaprio's character in Woody Allen's Celebrity (1998). In 2004, he earned his own group of hangers-on when he landed the lead role of Vince Chase on HBO's Entourage.
- Worked again with Woody Allen in 2003's Anything Else.
- A self-taught musician, he plays drums for the Honey Brothers under the moniker Honey DuContra.
- Produced the environmentally friendly TV series Alter Eco.
- 2008, Screen Actors Guild Awards — Outstanding Performance by an Ensemble in a Comedy Series: Nominee
- 2007, Screen Actors Guild Awards — Outstanding Performance by an Ensemble in a Comedy Series: Nominee
- 2006, Screen Actors Guild Awards — Outstanding Performance by an Ensemble in a Comedy Series: Nominee
- John Dunbar — Father
- Karesse Grenier — Mother
- Esther Dunbar — Grandmother
- Carl Dunbar — Grandfather
- Isabel Lucas — Ex-significant Other
- Attended Bard College, Annandale-on-Hudson, New York, United States
- Birth Place: Brooklyn, New York, United States
- Birthday: July 10, 1976, Cancer
- Profession: Actor, Director, Producer, Musician