The management at Major League Soccer outfit D.C. United watched the game tapes and signed the small playmaker with the club in 2002.
He returned to play in his native country but in 2008, Quintanilla signed a five-month deal with Costa Rican football club L.D.
On 16 December 2009, Mexican lower league side Correcaminos UAT confirmed acquiring Quintanilla on a six-month contract.
[6] Quintanilla made his debut for El Salvador, aged 16 years, in a February 2000 friendly match against Honduras and has, as of December 2011, earned a total of 59 caps, scoring 15 goals.
With the win, El Salvador advanced to Round 3 in the CONCACAF Zone in the World Cup Qualifiers for Africa 2010.