He stood 6 feet 5 inches (1.96 m) tall and weighed 230 pounds (100 kg) during an active career spent with the Los Angeles Dodgers, New York Yankees, Cleveland Indians, Minnesota Twins, St. Louis Cardinals and Boston Red Sox between 1958 and 1972.

After his playing days, Williams was a pitching coach for another 14 seasons for five Major League teams.

[3] He made his MLB debut on May 17, 1958, at the age of 21,[2] relieving Sandy Koufax and giving up three earned runs and striking out one over 3 innings in a 10–1 loss to the St. Louis Cardinals.

[4] He finished his rookie year with a 9–7 win–loss record, 4.01 earned run average (ERA), and 80 strikeouts over 119 innings pitched.

Williams gave up a sacrifice fly to Orlando Cepeda that tied the game, then threw a wild pitch and issued an intentional walk that re-loaded the bases.

He then walked Jim Davenport to force in what turned out to be the series winning run before he gave way to Ron Perranoski.

[2] Although his control often kept him from being a top pitcher, Williams' presence on the mound was huge, and many batters around the league feared the six-foot, five-inch right-hander, who had a blistering fastball and was not afraid to pitch inside.

Williams played his final major league game on August 1, 1972, just over a month before his 36th birthday.

In 1959, facing the Chicago White Sox, he threw two hitless innings in relief of Koufax in Game 5.

However, John respected Williams for his work ethic and noted that he was a great pitching coach for pitchers like Ron Guidry.