A prominent Tibetan filmmaker, who was jailed for making a documentary about Tibetans living under Chinese rule and had been under police surveillance since his release three years ago, has fled to the United States after an “arduous and risky escape” from China, according to his supporters.

Dhondup Wangchen, 43, arrived in San Francisco on Dec. 25 and was reunited with his wife and children, who were granted political asylum in the United States in 2012, according to Filming for Tibet, a group set up by Mr. Wangchen’s cousin to push for his release.

“After many years, this is the first time I’m enjoying the feeling of safety and freedom,” Mr. Wangchen said in the statement issued by the group. “I would like to thank everyone who made it possible for me to hold my wife and children in my arms again. However, I also feel the pain of having left behind my country, Tibet.”

Mr. Wangchen was a self-taught filmmaker from China’s western province of Qinghai who had spent five months in 2007 interviewing Tibetans about their hopes and frustrations living under Chinese rule. In his documentary, “Leaving Fear Behind,” many Tibetans talked about their love for the exiled Tibetan spiritual leader, the Dalai Lama, and how they thought the 2008 Beijing Olympics would do little to improve their lives.