He played in Major League Baseball (MLB) for the Colorado Rockies (2005–2009), Texas Rangers (2011), New York Mets (2012, 2013-2014), and Baltimore Orioles (2012).

Quintanilla attended Socorro High School in El Paso, Texas, where he played with fellow teammate DR Melo.

Quintanilla led the city of El Paso in home runs, RBI, and was elected to the Texas All-State shortstop.

Quintanilla started 2004 with Modesto as the Athletics' seventh ranked prospect and after hitting .315 received a late-season promotion to the Midland RockHounds for the Double-A Texas League.

On July 15, 2005, Quintanilla was traded along with outfielder Eric Byrnes to the Colorado Rockies in exchange for pitchers Joe Kennedy and Jay Witasick.

The Office of the Commissioner of Baseball announced August 11, 2010, that Quintanilla had received a 50-game suspension after testing positive for Methylhexaneamine, a performance-enhancing substance, in violation of the Minor League Drug Prevention and Treatment Program.

On September 1, Quintanilla was removed from the 40-man roster and sent outright to Round Rock, but rejected the assignment and elected free agency.

[5] On June 1, Quintanilla started at shortstop on the first ever no-hitter in New York Mets history thrown by Johan Santana, as the team shut out the St Louis Cardinals 8-0.