Hickman was born in L.A. on May 18, 1934, the younger brother of Darryl Hickman, who became a noted child actor in films.
Initially, Hickman followed his big brother into the movies, working as an extra in "The Grapes of Wrath" (1939) and "Men of Boys Town" (1941). He made his first credited film appearance in 1945's "Captain Eddie," and also had credited roles in "The Return of Rusty" (1946), "The Secret Heart" (1946), and "The Boy with Green Hair" (1948).
While his older brother remained a movie actor, Dwayne gravitated to TV, making his debut on the 1954 series "Public Defender." After appearing on "The Lone Ranger" (1951) and "The Loretta Young Show" (1954), he landed his breakthrough role, playing Chuck MacDonald on "The Bob Cummings Show" (1955-1959) for over 150 episodes.
He became a TV phenomenon as the star of "The Many Loves of Dobie Gillis" (1959-1963), an innovative show that was the first on a major network to focus on teenage characters as the stars. Hickman played the titular charming schemer, with Bob Denver as his beatnik sidekick. The series lasted nearly 150 episodes.
When his signature series was over, Hickman was nearly 30 years old and found himself typecast. He appeared in the film "Cat Ballou" (1965), but then felt compelled to sign up for a series of youth-driven American International Pictures films, including "Ski Party," "How to Stuff a Wild Bikini," and "Dr. Goldfoot and the Bikini Machine" (all 1965).
Hickman made numerous TV appearances in the '60s and '70s, including reprising his role as Dobie for the TV movies "Whatever Happened to Dobie Gillis?" (1977) and "Bring Me the Head of Dobie Gillis" (1988), last playing the part on an episode of "Hi Honey, I'm Home" (1992).
He also appeared on series like "Love, American Style" (1969, 1972 & 1973), "Kolchak: The Night Stalker" (1975), and "Murder, She Wrote" (1990), and made cameos in the TV movie "High School U.S.A." (1983) and the feature "A Night at the Roxbury" (1998).
His last recurring role was on the series "Clueless" (1996-1999), and his final role in any medium was in the 2005 movie "Angels with Angles."
After becoming disenchanted with the roles he was being offered, Hickman had taken to working behind the scenes, as both a TV director and producer. From 1977-1988, he was a programming exec at CBS. In his later years, he became a painter.
Hickman was married three times. He was wed to actress Carol Christensen from 1963-1972, Joanne Papile from 1977-1981, and is survived by his wife, actress and voice-over artist Joan Roberts, to whom he had been married since 1983.
He is also survived by his brother, Darryl, and by his two children.
Sheila Kuehl, who played lovestruck Zelda on "The Many Lives of Dobie Gillis" — and who is now a congresswoman from California — remembered Hickman in a series of tweets, writing, "Zelda still loves Dobie. I am so deeply saddened at the news that my dear friend over a 62-year span, and Many Loves of Dobie Gillis co-star, Dwayne Hickman, passed away this morning from complications of Parkinson's disease."
She went on, "It was such a joy and a privilege working with Dwayne, a true professional, a good man, a fine talent, a generous actor (always playing the straight man and giving us the laugh lines), and still one of the funniest and people I've ever known."
Referencing her coming out as a lesbian in the '90s, she recalled, "We grew up together on-screen and remained great friends. I'll never forget the warm, strong public support he gave me when I came out at a time when it was tough facing the national news outlets. And the same when I first put my toe in political waters in 1994. But that was Dwayne. A standup, sweet guy until the end, he'll be deeply missed by so many whose lives he touched. My deepest sympathies to Joan and Albert, John, and all his family and friends."