Conrad was born Conrad Robert Falk in Chicago. His father, Leonard Henry Falk (born October 25, 1917), was 17 years old at the time of Conrad’s birth and was of German descent. His mother, Alice Jacqueline Hartman (born May 15, 1919, daughter of Conrad and Hazel Hartman), was 15 years old when she gave birth, and named her son after her father. She became the first publicity director of Mercury Records, where she was known as Jackie Smith. She married twice, including once to Chicago radio personality Eddie Hubbard in 1948. Eddie Hubbard and Jackie Smith reportedly had a child together (born circa 1949) before splitting up in 1958.

In 1957, Conrad met actor Nick Adams while visiting James Dean’s gravesite in Fairmount, Indiana. They became friends and Adams suggested that Conrad move to California to pursue acting.

Conrad was soon signed to an acting contract by Warner Bros. He also sang, and released several recordings with Warner Bros. Records on a variety of LPs, EPs, and SPs 33-1/3 and 45 rpm records during the late 1950s and early 1960s. In 1961, he had a minor Billboard hit song in “Bye Bye Baby” which reached #113.

In Mexico, Conrad signed a recording contract with the Orfeon label. He released two albums with a few singles sung in Spanish. In 1964, he guest-starred on an episode of Temple Houston, then performed in the comedic film La Nueva Cenicienta (also known as The New Cinderella). The next year, he was in the episode “Four into Zero” of Kraft Suspense Theatre, and portrayed Pretty Boy Floyd in Young Dillinger alongside his old friend Nick Adams.

In 1965, Conrad began his starring role as government agent James West on the weekly series The Wild Wild West, which aired on CBS until its cancellation in 1969. He made $5,000 a week. He did most of his own stunts and fight scenes during the series, and while filming the season four episode “The Night of the Fugitives”, he was injured and rushed to the hospital after he dove from the top of a saloon staircase, lost his grip on a chandelier, fell 12 feet, and landed on his head.

In addition to starring in The Wild Wild West, Conrad found time to work on other projects. He went to Mexico in 1967 to appear in Ven a cantar conmigo (Come, sing with me), a musical. He also formed his own company, Robert Conrad Productions, and under its auspices he wrote, starred in, and directed the Western film The Bandits (also 1967).

Conrad appeared in episodes of Mannix and Mission: Impossible. In 1969, he signed a three-picture deal with Bob Hope’s Doan Productions. The first two films were slated to be Keene then No Beer in Heaven but only the first movie was ever produced.

In 1969, he debuted as prosecutor Paul Ryan in the TV movie D.A.: Murder One (1969). He reprised the movie in D.A.: Conspiracy to Kill (1971) and the short-lived 1971 series The D.A.. He was also in such made-for-television movies as Weekend of Terror (1970) and Five Desperate Women (1971). He tried another TV series as American spy Jake Webster in Assignment Vienna (1972), which only lasted eight episodes. He was a murderous fitness franchise promoter in a fourth season episode of Columbo (“An Exercise in Fatality”, 1974). Conrad starred in the feature films Murph the Surf (1975) and Sudden Death (1977). He reprised his role as Paul Ryan in the TV movie Confessions of the D.A. Man.

Conrad and his first wife Joan were married for 25 years and had five children. They amicably divorced in 1977. The same year he met his second wife LaVelda Ione Fann. He was 43 when he emceed the Miss National Teenager Pageant, which she won. Their marriage produced three children before their divorce in 2010. His two families were said to “get along famously.” Conrad was joined on some television shows by his sons, Shane and Christian, and his daughter, Nancy. Another daughter, Joan, became a television producer.

In 1978, Conrad starred in the short-lived TV series The Duke as Duke Ramsey, a boxer turned private eye. Conrad directed some episodes. In the late 1970s, he served as the captain of the NBC team for six editions of Battle of the Network Stars. Around this time reprised the role of West in a pair of made-for-TV films which reunited him with his West co-star, Ross Martin, The Wild Wild West Revisited (1979) and More Wild Wild West (1980).

Conrad made the occasional feature such as The Lady in Red (1979) for Roger Corman’s New World Pictures, where he played John Dillinger from a script by John Sayles. Conrad later played a modern-day variation of James West in the short-lived series A Man Called Sloane in 1979. Conrad directed some episodes.

In 1984 Conrad and his production company produced the film, “Hard Knox”. He played the lead role of US Marine Colonel Joseph Knox. The story reveals a senior Marine aviator who has reached his pinnacle as a flyer and now must face the decision of accepting a promotion to Brigadier General with a new ‘ground’ focused future in the Marines, or the possibility of retiring from the Corps and moving on in a different direction with his life. He makes the decision to return to the home of his youth – Mount Carroll, Illinois to visit his alma mater, a local military prep academy, and look up his mentor from more than 30 years ago. It is there, where the story of ‘Hard Knox’ begins to unfold. The film was shot in Mount Carroll at the former Shimer College.

in 1986 Conrad served as special guest referee for the main event of WrestleMania II that featured Hulk Hogan v King Kong Bundy inside a steel cage for the WWF Title.

Conrad appeared in the movie Samurai Cowboy in 1994. The following year, he created the TV movie Search and Rescue, in which he starred, which in turn led to a short-lived TV series, also created by Conrad.

On March 31, 2003, while on Highway 4 in California’s Sierra Nevada foothills near his Alpine County home, Conrad drove his Jaguar over the center median and slammed head-on into a Subaru driven by 26-year-old Kevin Burnett. Both men suffered serious injuries. Tried on felony charges, Conrad pleaded no contest, and he was convicted of drunk driving.

In 2005, he ran for President of the Screen Actors Guild. In 2006, Conrad recorded audio introductions for every episode of the first season of The Wild Wild West for its North American DVD release on June 6. The DVD set also included one of Conrad’s Eveready battery commercials; in his introduction, Conrad stated he was flattered to be parodied by Carson. He was inducted into the Hollywood Stuntmen’s Hall of Fame for his work on The Wild, Wild West series.

He was sentenced to six months of house confinement, alcohol counseling, and five years’ probation. A civil suit filed by Kevin Burnett against Conrad was settled the following year for an undisclosed amount. In 2005, Burnett died at age 28 from perforated ulcers; his family attributed them to his difficult recovery from the crash. Conrad suffered severe nerve injuries from the crash, leaving his right side partially-paralyzed.

Beginning in 2008, he hosted a weekly two-hour national radio show (The PM Show with Robert Conrad) on CRN Digital Talk Radio. He appeared in the documentary film Pappy Boyington Field (released in July 2010 on DVD) where he recounted his personal insights about the legendary Marine Corps aviator he portrayed in the television series. His last appearance on the radio show was July 18, 2019 and Mike Garey was his co-host.

In a 2008 interview, Conrad described Chicago Outfit made man and burglar Michael Spilotro as his “best friend.” Spilotro’s slaying was featured in the movie Casino. In 1984, Conrad was awarded a star on the Walk of Western Stars in Newhall, California.

Conrad died of heart failure in Malibu, California on February 8, 2020, at age 84.