Thursday on his 80th birthday he told Action News why it was time to step down.
Larson said, "I think it's only fair that I make the announcement now. I don't care what side of the fence you're on it's only fair to give people a chance to do their fund raising."
Two weeks ago Larson was rushed from the Hall of Records to the hospital with an irregular heartbeat but said he is fine now.
The district one supervisor knew a few years ago he would not seek re-election. "We decided this will be three terms. I'm 80 years old and I think it's time to smell the roses."
The Republican supervisor has endorsed long-time supporter Brian Pacheco to fill his seat. The Kerman dairy operator is a Democrat.
Larson said, "Yeah I believe he is registered but he's very conservative. He's probably more conservative than I am."
ABC30 political analyst Tony Capozzi explained, "That district is part urban but mostly agriculture. Agriculture is not Republican, it isn't Democrat. It's who's pro-agriculture."
Capozzi says Larson's decision could signal a shift on the board. Two seats will now be open with Supervisor Judy Case not running for re-election either. "Right now it's in favor of the conservatives, the Republicans. It's like a 4-1 vote every time on major political issues. I think now with two of the supervisors leaving that's going to open up a battle on who's going to control this board."
Capozzi expected unions, especially SEIU, to spend two million dollars on the Fresno county campaigns for two supervisorial seats.
Fresno City Council president Blong Xiong told Action News he will run against Brian Pacheco for Larson's supervisor seat next year.