"Stanley Tookie Williams is not just a regular old guy, he's an inspirator," the rapper and former Crips gang member told a crowd of about 1,000 outside the main gate of San Quentin State Prison. "His voice needs to be heard."
Williams, 51, is set to be executed Dec. 13. He was convicted in 1979 of murdering four people during two robberies in Los Angeles. He has exhausted his appeals and asked Schwarzenegger for clemency.
Williams and a childhood friend organized the Crips in 1971 in Los Angeles. In the years that followed, the gang did battle with its main rival, the Bloods, for territory and control of the drug trade, leaving hundreds dead.
CBS News correspondent John Blackstone reports that Williams' supporters promise growing demonstrations over the next three weeks but there are those who remain unconvinced Williams has changed.
"He has multiple incidents where he has been involved in violent acts while here on death row at San Quentin – batteries, assault on staff," said Lt. Vernell Crittendon, a San Quentin Prison spokesman.
Snoop Dogg, 33, whose real name is Calvin Broadus, said after he saw "Redemption," the award-winning television movie starring Jamie Foxx based on Williams' life, he realized he needed to contribute more to his community and to young people, in particular.
"I come from the east side of Long Beach, home of where gang-banging is an all-time must and Crippen is at an all-time high. I was once a Crip gang member," he said, adding that the music business helped him leave that life behind.
He now does youth outreach activities, including running a football league for youngsters.
"I didn't get this from somebody that was on the streets. I got this from Stanley Tookie Williams, a brother that was locked up on death row," he said, wearing a white T-shirt with huge black letters that said savetookie.org. "He inspired me to want to do something positive with my life and to go touch the kids."
The rapper had wanted to visit Williams on death row, but his application was denied by prison officials because of his criminal record. Snoop Dogg has been arrested several times for weapons and drug-related offenses, according to the California Department of Corrections and Rehabilitation.
Organizers played a new Snoop Dogg song called "Real Soon," which promotes Williams' advocacy work. It was expected to be available Monday as a download from the rapper's Web site.
Members of the black Muslim organization Nation of Islam along with California Highway Patrol and Marin County Sheriff's deputies provided security for Saturday's event. No incidents were reported.
Volunteers sold T-shirts, doughnuts and coffee. Paperback copies of Williams' memoir, "Blue Rage, Black Redemption" also were available. All proceeds were to benefit the Save Tookie Foundation, organizers said.
Sharnell Smothers, 23, of Oakland, California, attended the rally with two friends.
"I'm just here to support Tookie," she said. "He's changed his life. I just think he should have another chance."
Cassandra Gonzalez, a former Los Angeles gang member, was one of about a dozen speakers. She said she spent her teen years in and out of jail and there was little to help guide her out of the criminal justice system.
"We need (former gang members) in the neighborhood so they can guide lost souls like me," she said.
Williams has earned international acclaim for his children's books urging kids to stay out of gangs, among other peace-preaching efforts.
Todd Chretien, who works with the Campaign to End the Death Penalty, an advocacy group that helped organize the rally, implored the governor to grant clemency.
"There is no reason on earth to kill him, and there is every reason to keep him alive," he said.