Kline was signed by the Pirates in 1950. After 2 seasons in the minors, Ron made the Pirates at the start of the 1952 season. After dividing the season between the Pirates and their class-B team in Burlington, NC, Kline lost the ’53 and ’54 seasons to military service.
He returned in 1955, and for the next 5 seasons was one of the Pirates’ top 3 starters (along with Vern Law and Bob Friend). He missed out on the 1960 championship season, as he was traded to the Cardinals the previous winter.
After one season in St. Louis, Kline began the 1961 season as a starting pitcher for the expansion Los Angeles Angels. By mid-August, he was claimed off waivers by the Tigers. Ron spent the next season and a half with Detroit, and was converted to a reliever while with the Tigers.
Kline was sold to the Washington Senators during spring training 1963, and became the team’s top reliever for the next 4 seasons. He led the Sens’ staff in saves each year, topping out at 29 saves in 1965.
After the 1966 season he was traded to the Twins for pitcher Camilo Pascual and 2nd baseman Bernie Allen. Exactly 1 year later he returned to the Pirates in a trade for minor-league 1st baseman Bob Oliver (who would later star for the Kansas City Royals). In 1968 Kline compiled a 12-5 record and a 1.68 ERA in 56 relief appearances, pitching more innings than any season since 1961.
He split the 1969 season between the Pirates, Giants, and Red Sox, and was released by Boston before the 1970 season. The Braves signed Ron at the end of April, but after 5 relief appearances, he was released 2 months later. He spent most of 1970 pitching for the Angels’ AAA team in Hawaii before retiring.
Kline passed away in 2002 at age 70, in his hometown of Callery, PA a suburb of Pittsburgh.