She is best known for playing college softball at Arizona from 1993 to 1997, winning three National Championships, and earning gold medals at the 1996, 2000 and 2004 Summer Olympics.

Born in Garden Grove, California,[1] O'Brien-Amico graduated from Don Lugo High School in nearby Chino in 1992 and attended the University of Arizona.

At the 1993 Women's College World Series, the Wildcats faced rival UCLA in the finale and with the only hit allowed, she drove in the game-winning run off Lisa Fernandez.

Returning to defend their title at the WCWS, O'Brien-Amico hit .750 (9/12 with 5 RBIs, a home run and two doubles) to set the tournament record for batting average.

Concluding her finals streak at the WCWS, O'Brien-Amico won her third national championship over the UCLA Bruins and was a perfect 2/2 with two RBIs and two walks against hurler Christa Williams.

With combined stats from previous seasons, O'Brien-Amico had a WCWS career of .563 (31/55) with 19 RBIs, two home runs, 4 doubles and 7 walks, striking out just once with a slugging percentage of .745%.

She drove in her only RBIs in a 6-0 win over Italy and in the gold medal game was shut out by Japan, though Team USA won 2-1 on September 26.

[21] In the Olympics, O'Brien-Amico had a tournament-best 2 RBIs off Melanie Roche of Australia on August 15; the US eventually won 10-0 run-ruling the Australians.

[23] In the August 23 gold medal game, O'Brien-Amico had a single as the United States defeated Australia 5-1 to close out their dominating tournament in victory.