The filming location for Harvey Milk's business, Castro Camera, was the real storefront where the actual business had once been. At the time of filming (mid-2008), it was a gift shop called "Given"; the film crew worked with the owner of the gift shop to recreate the look of Milk's camera store inside the space and restored it to its 2008 appearance after filming.
During the filming of the scene in which Dan White's son Charles is christened, the real Charles White was on the set.
Thousands of people agreed to take part in the film as extras for free.
After his first kissing scene with James Franco, Sean Penn texted his ex-wife Madonna saying, "I just broke my cherry kissing a guy." Her texted response: "Congratulations."
Sean Penn's cosmetic transformation in the film included a prosthetic nose and teeth, contact lenses and a redesigned hairline. His makeup was done by Academy Award winner Stephan Dupuis.
Tom Ammiano: The California Assemblyman and former San Francisco Supervisor plays himself. He was a founder in the No On 6 Campaign.
Dustin Lance Black: one half of the couple that walks by the Castro camera shop after it's closed, when Harvey Milk is inside. One of the men asks if Harvey was going to win this time.