Born William James Adams, he became known for his work as a founding member of the Black Eyed Peas alongside Fergie, Taboo and apl.de.ap. With the Black Eyed Peas, he won seven Grammy Awards and three World Music Awards. He has also had a solo career and worked as a music producer.
He was raised in the Boyle Heights housing project in East Los Angeles and attended Palisades Charter High School, where he befriended Allan Pineda, another future member of the Black Eyed Peas.
He appeared in The Urbz: Sims In The City, which used The Black Eyed Peas' songs for its soundtrack. He won a Grammy Award for Best Rap Performance for "Let's Get It Started" in 2005.
He was raised in Los Angeles, California by his mother Debra Cain.
He wrote the song titled "Yes We Can," which supported the 2008 Barack Obama presidential campaign.