Following World War II, O'Brian moved to Los Angeles and found work on stage and in film. He got his big break when he was chosen to portray the legendary lawman Wyatt Earp on television. The Life and Legend of Wyatt Earp debuted in 1955 as the "first adult western" and it soon became one of the top-rated shows on television. During its seven-year run, Wyatt Earp consistently placed in the top 10 in the United States. He also appeared regularly on other programs in the 1960s. For example, he was a guest panelist on the popular Sunday night CBS program What's My Line? and served as a mystery guest three times.
The actor made a number of motion pictures, among them The Lawless Breed (1953), There's No Business Like Show Business (1954) and In Harm's Way (1965). He was a featured star in the two-hour premiere of television's Fantasy Island. Perhaps O'Brian's greatest distinction is that he is the last man that John Wayne ever killed on the screen in his final movie The Shootist (1976). O'Brian was a good friend of the Duke and said he considers this a great honor.
O'Brian recreated his Wyatt Earp role for two 1990s projects, Guns of Paradise (1990) and The Gambler Returns: Luck of the Draw (1991) with fellow actor Gene Barry doing likewise as lawman Bat Masterson for each. He also had a small role in the Danny DeVito/Arnold Schwarzenegger 1988 film comedy Twins, as one of several men who had "donated" the DNA that later became the "twins." In the film, Schwarzenegger thought he'd found his "father," when he met Hugh O'brian's character.
For his contribution to the television industry, Hugh O'Brian has a star on the Hollywood Walk of Fame at 6613-1/2 Hollywood Blvd. In 1992, he was inducted into the Western Performers Hall of Fame at the National Cowboy & Western Heritage Museum in Oklahoma City, Oklahoma.
One high school sophomore from every high school in the United States, referred to as an “ambassador,” is welcome to attend a state or regional HOBY seminar. From each of those seminars, two students are offered the opportunity to attend the World Leadership Conference (WLC). Many do not attend because it is quite expensive, but several funds and scholarships, such as the Jack Tawney Memorial Fund in the Central PA chapter, allow students to go for free.
The concept for HOBY was inspired in 1958 by a nine-day visit O’Brian had with famed humanitarian Dr. Albert Schweitzer in Africa. Dr. Schweitzer believed "the most important thing in education is to teach young people to think for themselves."
Hugh O’Brian’s message to young people is “Freedom to Choose” Here is his brief speech on this topic: "I do NOT believe we are all born equal. Created equal in the eyes of God, yes, but physical and emotional differences, parental guidelines, varying environments, being in the right place at the right time, all play a role in enhancing or limiting an individual's development. But I DO believe every man and woman, if given the opportunity and encouragement to recognize their potential, regardless of background, has the freedom to choose in our world. Will an individual be a taker or a giver in life? Will that person be satisfied merely to exist or seek a meaningful purpose? Will he or she dare to dream the impossible dream?
"I believe every person is created as the steward of his or her own destiny with great power for a specific purpose, to share with others, through service, a reverence for life in a spirit of love."