More than 300 people in the packed Campus Center Ballroom were present to hear Chris Herren declare, “At 24 years old, I became a needle drug addict.”

The former Boston Celtic came to UMass Boston on April 23 to promote “Project Purple: Stand Up Against Substance Abuse,” an initiative of his non-profit organization, “The Herren Project.”

Born and raised in Fall River, Herren attended Fresno State in California. He was traded to multiple NBA teams in a short amount of time because of his addiction, hopping from team to team in hopes that someone would want him as a player. Herren told the crowd he was a “convicted felon and public heroin user” by age 24, after shooting up heroin and getting in a car crash.

“Project Purple” aims to break the stigma and raise awareness of the dangers of substance abuse. The non-profit focuses on the positive treatment practices available to addicts and their families.

ESPN filmed a documentary about Herren’s substance abuse problem entitled “Unguarded,” which aired in Nov. 2011. The film was nominated for two Emmy awards and has launched Herren’s public speaking career around the nation.