California Lieutenant Governor Gavin Newsom has called recent progress on gay marriage “unbelievable.”

Newsom's involvement in the issue goes back more than a decade.

In 2003, then-San Francisco Mayor Newsom ordered city hall clerks to issue marriage licenses to gay and lesbian couples in violation of state law. Several thousand gay couples were married during the “winter of love,” but eventually the California Supreme Court ordered the city to stop and invalidated all the marriages.

During an appearance on Larry King Now, Newsom, 45, told host Larry King that he never thought he would hear in his lifetime a sitting president endorse marriage equality as President Barack Obama has.

“It's extraordinary to see that progress,” Newsom said in reference to increasing Republican support on the issue.

“I'm all for incrementalism in some ways but not when it comes to fundamental human rights, civil rights. And we have to be as bold as the problem is big. To deny people the ability to live their lives out loud and to fall in love and express that love and devotion and faith to one another was something that upset me. And I just didn't like the timid nature of my party on it.” (The video is embedded on this page. Visit our video library for more videos.)