After a brief playing career in minor league baseball, Rizzo transitioned into coaching and scouting. He became the director of scouting for the Arizona Diamondbacks in 2000. Rizzo joined the Nationals in 2007 as an assistant general manager. He succeeded Jim Bowden as the Nationals' general manager in 2009, and was promoted to team president in 2013.
Rizzo grew up in Chicago as one of four children. His father, Phil, was a former minor league baseball player who drove a truck for the city and scouted for the California Angels on a part-time basis. The Angels made him a full-time scout, as many of the players he identified reached the majors.
The Angels drafted Rizzo in the 22nd round, with the 554th overall selection, in the 1982 Major League Baseball Draft. He played for the Salem Angels (Class A Short Season), Peoria Suns (Class A) and Redwood Pioneers (Class A Advanced) from 1982 to 1984. After the 1984 season, the Angels released Rizzo. His father suggested that he was not skilled enough to reach the major leagues, and advised he attend college.
Three days after Bowden's sudden resignation on March 1, 2009, Rizzo was promoted on an interim basis by team president Stan Kasten. He was named the full-time Senior Vice President/General Manager on August 20, 2009. On October 19, 2010 Rizzo got a five-year extension and was promoted to Executive Vice President of Baseball Operations and General Manager. The last two years of this contract were club options.