He played for the New York Mets, Baltimore Orioles, Colorado Rockies and Arizona Diamondbacks of Major League Baseball (MLB).

[1][2] Mora became a cult hero in New York as he starred in the 1999 National League Championship Series, batting a clutch .429 with an OPS of 1.143, and throwing runners out at home plate and third base from his right field position.

He reached base in 32 straight games while using a 23-game hitting streak to temporarily become the American League batting leader.

Mora's season was cut short due to injuries (a bruised wrist and a partially torn ligament in his left knee), but finished with a .317 batting average, 15 home runs, and a .418 on-base percentage in 96 games.

Mora hit a career-high .340, finishing second in the AL batting race to Ichiro Suzuki's .372 mark; led the league in on-base percentage (.419); ranked fifth in slugging average (.562) and OPS (.981); sixth in runs (111), doubles (41) and times on base (264); eighth in hits (187), and ninth in total bases (264).

[21] Mora missed a few days of spring training as a precautionary measure despite not having any serious injuries after his automobile was struck from behind by another vehicle on Arizona State Route 101 on March 7, 2011.

[22] He was in the starting lineup on Opening Day, scoring a run while going hitless in five at-bats in a 7–6 victory over the Rockies at Coors Field on April 1.

After a 6–2 loss to the Cleveland Indians at Chase Field on June 29 in which he struck out as a pinch hitter for Zach Duke with one out and a runner on first base in the fifth inning, he was given his unconditional release effective the following day.

[7][21] He allegedly officially announced his retirement as an active player on December 29, 2011, though in mid-January, Mora corrected that claim by saying he still wished to play in 2012.

[24][25] Mora agreed to represent his native country, Venezuela, in the 2006 World Baseball Classic, but pulled out after being denied the third base position in favor of Miguel Cabrera.

[26] On July 28, 2001, Mora's wife Gisel gave birth to quintuplets at Johns Hopkins Hospital in Baltimore, Maryland.