In 1977, Milk became the first openly gay elected official of any major U.S. city. In 1978, Milk and Mayor George Moscone were shot and killed by former supervisor Dan White.
"Harvey Milk was a true American hero," Leno said in a prepared statement. "He gave hope to a generation of gay and lesbian individuals whose basic humanity and freedom had been denied and dishonored. His history is our history, and a day in his honor will preserve his legacy for generations to come."
"A state holiday honoring Milk's legacy will forever remind us of what the courage of one person can accomplish and of the critical work that still lies ahead to create a world where everyone can live openly and honestly," said Equality California Executive Director Geoff Kors.
The proposed Harvey Milk Day would be celebrated May 22 and would be organized so as not to generate state costs or increase the number of paid state holidays, Leno's office said.
A film about Milk's life and death is currently being filmed in San Francisco.
