Lone was born in October 1952 as Ng Kwok-leung (Chinese: 吳國良; pinyin: Wú Guóliáng) in Hong Kong. He was raised in an orphanage and later adopted by a Shanghainese woman. He began training in Beijing opera at Hong Kong's Chiu Chiu Academy. It was here, at the age of ten, where he was given the name "Johnny". He later chose the name Lone to reflect the fact that he was an orphan and for its similarity to Leung, part of his given name.

Sponsored by an American family, he left the Beijing opera troupe and emigrated to Los Angeles, California. In the United States, he married fellow Santa Ana Community College student Nina Savino in 1972, and gained American citizenship. The couple divorced in 1979. Lone also continued his performing arts studies at American Academy of Dramatic Arts in Pasadena, California. Eventually, he would move to New York City, in order to pursue a career on stage.

His first major role in films was as the title character in Iceman. He is probably best known for his portrayal of Puyi in The Last Emperor and crime boss Joey Tai in Year of the Dragon in the mid-1980s, as well as an opera performer playing female roles in M. Butterfly (with Jeremy Irons). Further international film appearances included the role of corrupt Hong Kong cop Ricky Tan in Rush Hour 2. In the 1995 film The Hunted he played dangerous Assassin Kinjo alongside Christopher Lambert.