Of Irish heritage, Connors was the son of Allan and Marcella (nee Lundrigan) Connors of Placentia Bay, Newfoundland who emigrated to Brooklyn, New York in 1920. Connors grew up with a sister named Gloria. He attended a private high school and later attended Seton Hall University in South Orange, New Jersey. He then dropped out in 1942 to join the Army at Camp Campbell, Kentucky and next went to West Point.

After his military discharge in 1946, he joined the newly formed Boston Celtics of the Basketball Association of America, but left the team for spring training with Major League Baseball's Brooklyn Dodgers. He played for numerous minor league teams before joining the Dodgers in 1949 for a few weeks. Later, in 1951 he also played for the Chicago Cubs. He was then sent to the minor leagues again, in 1952, to the Cubs' top farm team at the time, the Los Angeles Angels. Playing baseball near Hollywood proved to be fortuitous. He was spotted by an MGM casting director and cast in the upcoming Tracy-Hepburn film Pat and Mike, in which he played a state police captain.

Connors was best known for his television work. He appeared in a 1954 episode of The Adventures of Superman titled Flight to the North, in which he played a good-natured (and very strong) backwoods fellow named Sylvester J. Superman.

He starred in the television Western series The Rifleman (1958-1963) and Branded (1965-1966), as well as the 1967 Cowboy in Africa TV series, alongside Ronald Howard and Tom Nardini. In 1973 and 1974 he hosted a television series called Thrill Seekers. He had a key role as a slaveowner in the famous 1977 miniseries Roots.

In 1991, he was inducted into the Western Performers Hall of Fame at the National Cowboy & Western Heritage Museum in Oklahoma City. Connors was frequently a supporter of the Republican Party, and attended a few fundraisers for campaigns of President Richard Nixon, who reportedly was a fan of Connors.

Chuck Connors died of lung cancer in 1992 at the age of 71 in Los Angeles, California.