There are 309 inmates serving life-without-parole sentences in California for murders committed when they were younger than 18.
Brown signed SB9 by Democratic Sen. Leland Yee of San Francisco on Sunday. The bill would let the inmates ask judges to reconsider their sentences after they serve at least 15 years in prison. Then, judges could reduce the no-parole sentence to 25-years-to-life if the inmate shows remorse and is taking steps toward rehabilitation.
Yee said SB9 recognizes that young people's brains and ability to control impulse change as they age. The bill was opposed by the state's major law enforcement and victims' organizations.
California is one of 39 states that allow judges to sentence minors to die in prison. More than 2,570 people convicted as juveniles are serving life sentences without the possibility of parole in the U.S., according to the Youth Justice Coalition, an Inglewood-based group concerned with the treatment of juvenile offenders.
The Associated Press contributed to this report.