Rosenthal was 91. He passed away Friday at a nursing home in Hollywood, where he had been treated recently for pneumonia.
He served in the Legislature for 24 years, mostly from the Westside of Los Angeles, Beverly Hills, Hollywood and the San Fernando Valley.
Rosenthal was first elected to the Assembly in 1974. He moved to the state Senate in 1982, and served in that chamber until 1998.
"He was one of the really decent people in what can be a very nasty business," said Larry Berg, retired director of the Jesse Unruh Institute of Politics at USC.
Gov. Arnold Schwarzenegger said Rosenthal left California "a better place."
Rosenthal was born in 1918 in St. Louis, the son of a garment industry pattern cutter and a homemaker. The family moved to Los Angeles in 1929, lured in part by the opportunity posed by the developing West -- but also "to escape the concept of winter," said Rosenthal's son, Joel.
Rosenthal served in the Navy during World War II, then went back to school to learn the printing business. With a partner, he owned a typesetting firm for more than 40 years.
Rosenthal and his wife, Patricia, were married for 62 1/2 years, and during his political career they were considered a full-fledged team in the state Capitol.
The Rosenthals traveled together each week to Sacramento, returning to Los Angeles every Thursday evening. They maintained that schedule in part to meet with constituents, their son said, but primarily to make time for family, including two children and three grandchildren. The entire family went to brunch every Sunday.
"As passionate as he was about politics and California, he loved his family," his son said.
Rosenthal undertook a host of causes in politics, particularly in the arenas of consumer protection and healthcare. He was a leader in Southern California's Jewish community, serving as president of the National Assn. of Jewish Legislators.
He also was an early leader on some issues that only later came to the fore nationally, particularly in predicting how the swelling ranks of the uninsured would foster a healthcare crisis and in attempting to free California from dependence on foreign energy sources by committing to alternative fuels, electric vehicles and other environmental initiatives.
"He was not a politician. He was a statesman," said his daughter, Suzanne Hellerstein.
Rosenthal fought hard against term limits, which he predicted would hand unprecedented power to lobbyists, create a divisive political climate and do away with institutional knowledge. Ultimately, it was term limits that ended his political career, forcing him from the Senate in 1998.
Rosenthal remained active late in life, serving on the state Fair Employment and Housing Commission well into his 80s.
Rosenthal is survived by his wife, who is 92; his son, Joel, 61, of Valley Glen; his daughter, Suzanne Hellerstein, 58, of Seattle; and three grandchildren, Helena Rosenthal, 23; Myra Hellerstein, 25; and Toba Hellerstein, 22.
Services will be at 11 a.m. Tuesday at Hillside Memorial Park in Culver City.