[1] Aguilera attended Edgewood High School in West Covina, California, and played third base for their baseball team.

[3] Aguilera saw his first MLB action on June 12, pitching two innings of scoreless relief and getting the win against the Philadelphia Phillies in a game started by Ron Darling.

That season, he was involved in a fight with Houston police outside a disco which resulted in the arrest of not only himself, but also teammates Bob Ojeda, Tim Teufel, and Darling, later referred to as 'Cooters-gate'.

Despite a 12.00 ERA in the World Series, he was the pitcher of record in the Mets' dramatic Game 6 comeback victory, getting the win despite giving up the two runs which surrendered the lead to Boston in the top of the 10th inning.

[9] After the Mets lost their seventh game in a row ahead of the trade deadline, Aguilera was included in a last-minute deadline deal,[10] along with West, Tapani, reliever Tim Drummond and a player to be named (which on October 16 became reliever Jack Savage), for Minnesota Twins ace Frank Viola.

[11] With the Twins well on their way to finishing 44 games behind the AL Central division winning Cleveland Indians in 1995, Aguilera was traded to the Red Sox on July 6 in exchange for minor league outfielder J. J. Johnson and pitcher Frank Rodriguez.

The following season, the experiment of Aguilera as a starting pitcher had ended midway through spring training and the veteran returned to the bullpen.

In 1999, Aguilera had gone 3–1 with 6 saves and a 1.27 ERA in 17 games before the Twins traded the 37-year-old and pitcher Scott Downs to the Chicago Cubs for Kyle Lohse and Jason Ryan.

Aguilera pitched well for the Cubs in 1999, posting a 6–3 record with 8 saves and a 3.69 ERA in 44 games as a middle reliever, set-up man, and occasional closer.

[17] Aguilera was on top of the Twins / Senators franchise list for career saves with 254 until Joe Nathan surpassed him on August 10, 2011.

[13] A devout Christian, Aguilera now lives in the San Diego suburb of Rancho Santa Fe, California and dedicates his time to his family and real estate investments.