A five-time judo champion in his teens, he attended jockey school from 1989 to 1991 then began his professional riding career in 1992.
In 1996, Coa returned to the U.S. to compete at racetracks in Florida, where he became the leading jockey at Calder Race Course in 1996, 1997, 1999, and 2000.
In addition, he was the leading jockey at Calder Race Course's Tropical Park meet in 1998 and 1999.
On December 29, 2006, he joined Hall of Fame inductees Angel Cordero Jr., Steve Cauthen, and Mike E. Smith as the only jockeys in the history of NYRA to win 300 races in one year.
Coa was temporarily paralyzed from the neck down and lost part of his lungs after fracturing his C-4 vertebra in a racing accident at Gulfstream Park on February 18, 2011, In spite of being designated a quadriplegic with little hope for recovery, he beat the odds and is now walking on his own and progressing toward what he hopes will be a full recuperation.