- Height 5' 11", Weight 200 lb.
- High School Fullerton (CA) High School
Alfonso Marquez was the first major league umpire born in Mexico. Marquez began his career in the 1993 Northwest League, then worked inthe 1994 Midwest League, 1995 California League, 1996-1997 Southern League and 1998-1999 Pacific Coast League.
In 1999, he made it to the major leagues as one of the umpires promoted to the National League when the Major League Umpires Association implemented its failed mass resignation strategy. He was integrated in the consolidated major league staff in 2000 and has been a full-time umpire ever since. In 2009 he was limited to only 7 games because of an injury; he also missed time in 2014. He worked the World Series in 2006, 2011 and 2015, as well as the 2006 All-Star Game, the 2018 All-Star Game and the 2013 World Baseball Classic.