As a pitcher

Taylor entered pro baseball in the Cleveland organization in 1956, attending university during off-seasons. After steady progress up the ladder in the Indians' farm system through 1961, he made Cleveland's Opening Day roster in 1962. On April 11, the Indians' second game of the regular season, Taylor drew the starting assignment against the Boston Red Sox at Fenway Park. He proceeded to throw 11 shutout innings and collect two hits in four at bats at the plate—one half of the Indians' hit total against Boston starter Bill Monbouquette. But in the 12th inning of the scoreless tie, Taylor loaded the bases with no out, then surrendered a game-deciding, walk-off grand slam home run to Carroll Hardy and was charged with the 4–0 defeat.^[3] Appearing in eight games pitched for the Indians, he returned to the minor leagues after May 20 and spent the rest of the year in Triple-A. Then, on December 15, Cleveland traded him to the Cardinals to obtain first baseman Fred Whitfield.

Taylor spent the remainder of his pitching career in the National League. With the 1963 Cardinals, he worked in 58 games and posted nine wins, two complete games in nine starts, 11 saves, and an earned run average of 2.97. The following year, his eight wins and eight saves contributed to the Cardinals' successful, 11th-hour drive to the 1964 National League pennant. In the World Series that followed, Taylor worked in two games and threw 42⁄3 hitless innings against the New York Yankees; notably, he went four innings in Game 4 at Yankee Stadium to preserve Roger Craig's 4–3 triumph and get credit for a save. When the Redbirds prevailed in seven games, Taylor earned his first World Series ring.

He then suffered through two off-years in 1965 and 1966. In 1965, Taylor appeared in 25 games for St. Louis through June 15, then was traded to the Astros for left-handed relief specialist Hal Woodeshick. He pitched poorly in Houston for the next season and a half, winning only three of 11 decisions (with four saves), and logged a nightmarish 6.03 earned run average in 68 total games pitched. On February 10, 1967, former Cardinals general manager Bing Devine, now president of the Mets, purchased his contract and revitalized his career.^[2]

Although the five-year-old Mets remained a second-division team in both 1967 and 1968, Taylor enjoyed two sparkling campaigns coming out of the New York bullpen, with 22 saves in 108 total relief appearances and a composite ERA of 2.47. Then, in 1969, Taylor was a key member of the "Miracle Mets," who stunned baseball by rising from their ninth-place 1968 finish all the way to the world championship. Taylor formed half of a formidable bullpen duo with left-hander Tug McGraw, leading the club in games pitched (59) and saves (13), winning nine of 13 decisions, and posting an effective 2.72 earned run average during the regular season. He then pitched 31⁄3 innings of scoreless relief in the 1969 National League Championship Series against the Atlanta Braves, allowing just three hits in his two appearances, and gaining credit for a victory in Game 2. Then, in the 1969 World Series against the favoured Baltimore Orioles, Taylor worked in two games, surrendered no hits in 21⁄3 innings pitched, and saved Jerry Koosman's Game 2 victory that kick-started the Mets' five-game Series triumph. Thus, in his four career World Series games, Taylor allowed no hits and only two bases on balls in seven full innings, with five strikeouts, and faced the minimum of 21 hitters.^[4]

Taylor remained a Met in 1970 and 1971 and posted seven more wins and 15 saves in 102 total games, although his ERA rose to 3.79. Then his contract was sold to the Montreal Expos, who released him on April 20, 1972, without bringing him into a game. Taylor signed with the Padres, but was ineffective in three of his four appearances in a San Diego uniform; on May 14 against Montreal at Jarry Park Stadium, he gave up home runs to Ken Singleton and Ron Fairly in his final major league pitching appearance.

Over his regular-season career, Taylor compiled a 45–43 won–lost record, 74 saves and three complete games in 491 appearances, 474 of them as a relief pitcher. In 800 innings pitched, he allowed 794 hits and 209 walks, striking out 464. His career ERA was 3.93. He posted a .103 batting average (12-for-116) in his major league career. He was good defensively; Taylor made only three errors in 169 total chances for a .982 fielding percentage, which was 27 points higher than the league average at his position. In his post-season career, including the 1969 NLCS, he was 1–0 with three saves and a 0.00 ERA in six games pitched, permitting only three hits in 101⁄3 innings pitched.

As a physician

After his playing career ended in 1972, Taylor entered medical school at the University of Toronto, having been inspired to do so after visiting field hospitals while on a USO goodwill tour during the Vietnam War.^[5] Taylor received his medical degree in 1977; two years later, he returned to baseball as the team physician of the Toronto Blue Jays, serving in that role for three decades,^[6] including during the Jays' 1992 and 1993 World Series championships. He also opened a private practice in Toronto, retiring from medicine in 2014.^[2]

Ron Taylor was inducted into the Canadian Baseball Hall of Fame in 1985, Canada's Sports Hall of Fame in 1993, and the Ontario Sports Hall of Fame in 2010.^[6][7] He was appointed a member of the Order of Ontario by the province's lieutenant governor in 2005.