According to a 1981 profile in People, Hamill's "first serious love" was actor Anne Wyndham, cast as his sister on General Hospital, with whom he had an offscreen relationship. He would later describe experiencing seasons of on-set awkwardness while working with her after their relationship ended. In a 2017 interview, he attributed his long, happy marriage to a non-actor to learning, through his relationship with Wyndham, the dangers of being in a relationship with a fellow actor.On December 17, 1978, Hamill married dental hygienist Marilou York in a private civil ceremony. They have three children: Nathan Elias (born June 1979), Griffin Tobias (born March 1983), and Chelsea Elizabeth (born July 1988). Nathan was born during the production of The Empire Strikes Back and had a cameo appearance as one of the Royal Guards of Naboo in Star Wars: Episode I – The Phantom Menace. Chelsea made a photographic appearance as an infant Axel Walker in the 1990 television series The Flash; the same photograph was used in the 2014 series. All three have cameos as Resistance soldiers in The Last Jedi.On January 11, 1977, before shooting one of his scenes in Star Wars, Hamill was in a car accident in which he fractured his nose and left cheekbone. As a result, a double was used for the landspeeder pickup shots. According to a recorded interview, he was driving his BMW on a freeway, became distracted, and seeing that he was missing his offramp, attempted to negotiate four lanes of traffic. Hamill later said that the stories surrounding his injuries had become exaggerated. Confirming that he had only broken his nose, he observed that "over the years it's [been] built up into having my face reconstructed with plastic surgery."Hamill is an outspoken supporter of Democratic Party candidates. Prior to the 2012 presidential election, he referred to Mitt Romney as a "snake oil salesman". He endorsed P.G. Sittenfeld in the 2016 Ohio Senate election. He has also criticized the tweets of Donald Trump by reading them out in his Joker voice.Hamill is a lifelong fan of Laurel and Hardy. In June 2016, he called into The Ross Owen Show on Black Sky Radio to talk for over an hour about his passion for Stan and Ollie. He was also an early fan of David Letterman, having occasionally appeared on Late Night with David Letterman, as well as taping every episode and keeping a journal documenting the show. After encountering writer Chris Elliott, Hamill was asked for assistance in helping determine the 1,000th Viewer Mail that Letterman had answered. His practice continued to Letterman's new show on CBS, but eventually stopped.He became a supporter of English football club Wolverhampton Wanderers F.C. in 2017.In December 2017, Hamill became an affiliate member of the Royal Society of Chemistry, having had an interest in the science since childhood.