Genser served on the City Council since 1988 and was elected mayor three times by the council.
"The city was his life. He dedicated all of his energies to the people of Santa Monica," Councilman Richard Bloom said. "His signature issue was affordable housing. But compassion for people underlined all that."
He was extraordinarily active despite longtime physical ailments that made it difficult to walk. "In spite of having very serious physical restrictions, he just never let any of that get in the way of taking care of his business," Bloom said.
Genser was born Nov. 18, 1950, in Los Angeles and graduated from Inglewood High and UC Berkeley, his sister said.
Genser became active in politics when the federal Housing and Urban Development agency unveiled plans to alter the historic Sea Castle residence on the Santa Monica shore, where Genser lived at the time. He helped found the Community Corp. of Santa Monica and was active in Santa Monicans for Renters' Rights.