Cory is the nephew of former light heavyweight and heavyweight world champion Michael Spinks. He is one of three boxing brothers: older brother Leon Calvin was a top St. Louis amateur and 1-0 as a pro when he was murdered in 1993, older brother Darrell Spinks is an active pro. He's a southpaw with good skills, handspeed, and mobility. He's known for keeping a busy pace, keeping his opponents off-balance, and outworking them. Spinks also has a strong amateur background. He won in first major title in March of 2002, when he defeated Michele Piccirillo by unanimous decision.

Cory started boxing at the age of 16. His current trainer and former St. Louis policeman Kevin Cunningham, opened a boxing gym in the basement of an old police building. This is where Cory and his brother Darrell were introduced to the sport. Cunningham was also a former boxer in the Army.

Spinks was the 1997 National Golden Gloves champion at 147 pounds, and the 1997 National PAL champion at 147 pounds. In the National PAL finals, Cory won a 4-1 decision against Dante Craig, who went on to make the 2000 US Olympic team.

Cory reportedly had 81 amateur bouts (78-3). he also won the National PAL Jr. championships in 1993.

Spinks rose to boxing stardom by unifying the WBC, WBA, IBF, and Ring Magazine welterweight titles on December 13, 2003, when he defeated Ricardo Mayorga by majority decision. Spinks was a 5 to 1 underdog going into the fight with Mayorga. Two judges had it for Spinks, 117-110 and 114-112, and the third had it 114-114. Had Mayorga not been docked two points by referee Tony Orlando in the fifth round for hitting after the bell and in the 11th for holding and hitting the fight would have ended in a draw.

In his first title defense on April 10, 2004, Spinks controlled the action against former world champion Zab Judah over the first four rounds. In the later rounds, however, Judah's quick left hands began to find their target. Both men hit the deck late, but all three scorecards favored Spinks as the champion won 116-111 and 114-112 (twice).

He later lost his titles when he was TKO'd in the 9th round by Judah in their February 2005 rematch in front of a record crowd of over 22,000+ at the Savvis Center in St. Louis, Missouri. Spinks got the star treatment during introductions, with rapper Nelly accompanying him into the ring and leading the crowd in a singalong.

The fight was the first major bout in St. Louis in more than 40 years, and it was a sellout, helped by Spinks' large following. Midway through round 9, Judah landed a huge left that hurt Spinks, with a follow-up putting him on the canvas. Spinks rose, but Judah rushed in for the kill. A series of hard punches left Spinks defenseless on the ropes, and Judah tried to get the official to step in, but the bout continued until another right left sent Spinks sprawling into the ropes, where the official finally halted the bout with 11 seconds left.

Spinks moved up one weight class to 154 pounds to fight Roman Karmazin on July 8, 2006. This bout was once again held in the Savvis Center. Spinks beat Karmazin by majority decision. Spinks was able to get the victory despite being rocked with a solid left to the side of the head with about 30 seconds left in the 10th round. The judges final scorecards read, 114-114, 113-115 and 113-115. Karmazin was fighting for the first time since defeating Kassim Ouma on July 14, 2005.