[2] Hunter retired at age 33 following the 1979 season, after developing persistent arm problems, and was inducted into the Baseball Hall of Fame in 1987.

Hunter has been the subject of numerous popular culture references, including the Bob Dylan song "Catfish".

Hunter played linebacker and offensive tackle in football as well as shortstop, cleanup batter, and pitcher in baseball.

[6] Hunter signed with the A's on June 8, 1964, for a reported $75,000, but did not play professionally during the 1964 regular season due to foot surgery and the subsequent recovery from his hunting accident the previous fall.

[3][4] A story circulated that his family gave him the nickname as a child when he went missing and was later found with a string of catfish; there is no truth to that explanation.

[9] He made his major league debut in May, 1965 and earned his first win on July 27 in Fenway Park over the Boston Red Sox.

Hunter's statistics while he was with the Athletics were impressive: four consecutive years with at least 20 wins, and three World Series championships without a loss.

On February 11, 1974, Hunter agreed with the A's on a two-year, $200,000 contract with a clause stipulating that $50,000 payments be made to a life insurance annuity of his choosing in each of the two seasons.

After Finley refused to make payment on the annuity after discovering he had to pay $25,000 in taxes which was due immediately, the breach of contract dispute was brought before an arbitration hearing on November 26, 1974.

[12] Twenty days later on December 16, arbitrator Peter Seitz decided in favor of Hunter, officially making him a free agent.

In 1976, Hunter became the fourth major league pitcher to win 200 games before the age of 31 and the only one since Walter Johnson in 1915, preceded by Cy Young and Christy Mathewson.

After the designated hitter was adopted by the American League in 1973, Hunter had only two plate appearances in his final seven seasons, with one base hit in 1973.

Hunter won his Opening Day start in 1977, limiting the Milwaukee Brewers to three hits over seven shutout innings in a 3–0 victory on April 7.

In spring training, he was diagnosed with diabetes[31][32] and combined with his chronic arm trouble the disease began to sap Hunter's energy.

[35] He returned to his farm in Hertford where he grew soybeans, corn, peanuts, and cotton, and was a spokesman for diabetes awareness.

[40] Hunter is interred at Cedarwood Cemetery in Hertford, adjacent to the field where he played high school baseball.

Before and after his induction, Hunter spoke highly of his experiences with both the Athletics and Yankees and his appreciation for both team owners, Charlie Finley and George Steinbrenner.

On September 5, 2018, Hunter was inducted into the Oakland Athletics first Hall of Fame class, with his widow, Helen, in attendance to receive the posthumous honor.

When Coach Morris Buttermaker (Walter Matthau) is trying to get Amanda Wurlitzer (Tatum O'Neal) to pitch for his Little League team, Amanda makes a number of outlandish demands (including imported jeans, modeling school tuition, and ballet lessons) as conditions for joining the team.

In the movie Grumpier Old Men, an enormous and highly prized fish is named "Catfish Hunter" by the locals.

Minor-league pitcher Jason Kosow portrayed Hunter in the ESPN miniseries The Bronx is Burning, which depicted the 1977 New York Yankees.