competed from 1990 to 2012. He held the WBA featherweight title from 2000 to 2003. In 2000, Gainer defeated Freddie Norwood to win the WBA featherweight title and after four defenses lost to Juan Manuel Márquez, who became super champion, via technical decision in 2003. Since his defeat to Marquez, Gainer lost in a challenge to WBA titleholder Chris John via unanimous decision. Gainer is also a colleague and good friend of fellow Pensacola, Florida native Roy Jones Jr., and often fought on his under-cards.[citation needed]His last was a split decision win over Carlos Navarro on the undercard of the Roy Jones-Anthony Hanshaw bout at the Mississippi Coast Coliseum, in Biloxi, Mississippi. Derrick started a charter high school for at risk kids in 1999 which he named after his late grandmother Dr. Ruby J Gainer. This year Gainer started Fit Nation which is a childhood obesity program with goals to help kids make healthy life style changes.

DERRICK GAINER vs:
RUNNELL DOLL...............Fight #09
ROY SIMPSON.................Fight #11
GREG TORRES.................Fight #13
ROBERTO GARCIA.........Fight #14
HAROLD WARREN #1....Fight #15
KEVIN KELLEY #1............Fight #18
MANUEL MEDINA...........Fight #22
ORLANDO SOTO............Fight #24
KEVIN KELLEY #2...........Fight #25
BERNARD HARRIS........Fight #26
FREDDY CRUZ.................Fight #27
SERGIO REYES...............Fight #30
DIEGO CORRALES........Fight #32
SEAN FLETCHER….......Fight #39 
RICHARD CARRILLO...Fight #40
FREDDIE NORWOOD...Fight #41
VICTOR VOLO................Fight #42
CEDRICK MINGO…......Fight #43
DANIEL SEDA.................Fight #44
OSCAR LEON.................Fight #45
JUAN M. MARQUEZ......Fight #46