Ronald Clarence Kulpa
- Height 6' 2", Weight 220 lb
- School Missouri Baptist College, Florissant Valley Community College
- High School Hazelwood Central High School
Ron Kulpa went to umpiring school after college. He made his Organized Baseball debut in the Northwest League in 1992, then moved up to the 1993 Midwest League, 1994 Carolina League, 1995-1996 Southern League, 1997 Texas League and 1998-1999 Pacific Coast League. He umpired a couple of National League games in 1998, then worked as a replacement umpire in 1999 before being hired full-time as a result of the mass resignation of umpires at the end of that season. He joined the major league umpiring staff in 2000 when the two leagues pooled their umpires and has been a major league umpire ever since. He has since worked the 2001 All-Star Game, Justin Verlander's 2007 no-hitter, the 2009 World Baseball Classic and the 2011 World Series.
Kulpa made a controversial call in the 4th inning of Game 3 of the 2011 World Series. Working first base at the Rangers Ballpark in Arlington, he called the St. Louis Cardinals' Matt Holliday safe at first on a relay that pulled Texas Rangers first baseman Mike Napoli off the bag in an attempt to complete a double play. Television replays showed that Napoli had in fact tagged Holliday before he reached first, and the Cardinals used the extra out to put up a four-run inning, taking a 5-0 lead on their way to a 16-7 win. On August 12, 2013, he was behind the plate when Yu Darvish of the Rangers made a bid for a perfect game against the Houston Astros. Having retired the first 17 batters of the game, Darvish caught Jonathan Villar looking at a low pitch on a 1-2 count in the 6th; both Darvish and C A.J. Pierzynski started heading for the dugout, certain they had recorded an inning-ending strikeout, before Kulpa called them back, calling the pitch a ball. Villar eventually drew a walk, and Kulpa tossed an incensed Pierzynski from the game, as he continued to argue the previous call. Darvish ended up giving up only that walk and one hit, but to Kulpa's defence, the controversial pitch did appear to be low in spite of the Rangers' fervent wishes otherwise.
Another controversial call came in the New York Mets' home opener on April 8, 2021. With the score tied, the bases loaded and a full count, a pitch by Anthony Bass of the Miami Marlins grazed Michael Conforto's elbow. The hit-by-pitch pushed across the winning run, but replays made it clear that 1) the pitch was in the strike zone and 2) Conforto had made no effort to get out of the way (and in fact seemed to move into the pitch). After the game, Kulpa recognized that he had blown the call and should have called strike three.