He was drafted by the Colts with their first pick, the second overall in the first round. He was considered the best athlete in the draft. When the Tampa Bay Buccaneers took Miami quarterback Vinnie Testaverde, the Colts had a real no brainer on their hands in choosing Bennett. Bennet wouldn't come cheap however. Other linebackers chosen in the first round, most notably Brian Bosworth (Seattle) and Shane Conlan (Bills), would sign million dollar contracts with their teams and Bennett wanted more than they had signed for and Indy wasn't anxious to pay an unproven rookie those kind of figures.
On Halloween, the Bills sent running back Greg Bell, their 1st. round draft pick in 1988 and their 1st. and 2nd. round picks in 1989 to the Colts for Bennett. The Colts sent the entire package as well as their own 1st. and 2nd. rounders in '88 and a 2nd. rounder in '89 plus running back Owen Gill to the Rams for running back Eric Dickerson. The Bills signed Bennett for five years for $3.875 million. Said Buffalo general manager Bill Polian, explaining the logic behind the trade, "Right off, Bennett is our number one pick for 1988. If he does for us what I think he'll do, we would be picking in the middle of the first round next year or higher up the next year. Who knows who we'd get? As it turns out, we get Bennett a year ahead of time."
In his first game as a Bill against the defending AFC champion Denver Broncos, Bennett didn't start but was put in on passing situations. He had one sack, three tackles and two quarterback pressures, as the Bills stunned the Broncos 21-14. He would start in the next 7 games, finishing the season with 69 tackles, 8.5 sacks, 7 QB pressures and force a team high 5 fumbles. All in only eight games.
In 1988 Bennett, as well as the Bills began to blossom. In helping the Bills win their first AFC Eastern Division title in eight years, Bennett and the Bills defense gained respect throughout the NFL. He was selected to the Pro Bowl, his first of 5, and was chosen as AFC co-defensive player of the year, sharing the honor with teammate Bruce Smith. He finished the season with 103 tackles (a team high 85 primary tackles), 9.5 sacks, 3 fumble recoveries, 3 fumbles forced and two interceptions.
1989 was considered an off year for Bennett. Injuries hampered his play all season long, it was also the year of the "Bickering Bills." Dubbed this because of the whining done off the field throughout the season. Fans became disenchanted with the Bills behavior and uninspired play and the biscuit was an easy target for their scorn. Some talk was going around that he was overrated and that maybe the Bills gave away too much to get him. Bennett still finished the season with 5.5 sacks and two fumble recoveries, not bad for an off year.In 1990, the Bills would put it all together, enjoying their finest season ever.In the 4th game of the season Cornelius Bennett was responsible for sending the Bills on their way down the road to the Super Bowl. The Bills were trailing the Broncos 21-10 in the 4th. quarter. The Broncos then drove to the Bills 6 and were attempting a field goal that would have put the game away when Nate Odomes blocked the kick and Bennett picked up the ball and ran 80 yards for the TD. Bennet would recover another fumble later in the game, as the Bills went on to win, 29-28. The following week lightning would strike again as the Bills came from behind to beat the Raiders, 38-24. Bennett was instrumental in this game also, as he had two sacks, a forced fumble and fumble recovery, that set up a Bills field goal. He would finish the season with 96 tackles, 4 sacks, 2 fumble recoveries and 3 forced fumbles, good enough for a return trip to the Pro Bowl.
In 1991 the Bills would return to the Super Bowl again and Bennett would enjoy his finest season. Injuries to Bruce Smith and nose tackle Jeff Wright forced the Bills defensive decision makers to move the Biscuit to inside linebacker to compensate for the losses. He would respond by finishing with 107 tackles, a team high 9 sacks, 4 forced fumbles and 2 fumble recoveries. Earning another trip to Hawaii and being named AFC defensive player of the year, once again.
During the remainder of the Bills Super Bowl run, Bennet would be chosen to the Pro Bowl in all 4 years. In 1995, Bennett would move to the inside again and have another stellar season for the Bills, as they returned to the playoffs after a one year hiatus. Cornelius Bennett would lead the team in tackles and was seemed to be a fixture on the Bills defense for the remainder of his career, unfortunately this would not be the case however. Before the 1996 season, Cornelius Bennett, an unrestricted free agent, would sign a contract with the lowly Atlanta Falcons which included a $5 million signing bonus. The Bills didn't have that kind of room under the salary cap to match that offer and the Biscuit was gone.
In 1998 the Falcons had a tremendous season and Cornelius Bennett made it to the Super Bowl, once again. Alas, the Falcons lost to the heavily favored, Denver Broncos and Bennett became the first player in NFL history to lose 5 Super Bowls. He has since been released by the Falcons and was picked up by, ironicly, the Inianapolis Colts, the team that originaly drafted him. In 1999 Bennett was signed by Colts' GM, Bill Polian, were he ironicaly played for the Colts for two seasons before being released.
After leaving, many critics would lament that no player is worth $5 million. Detroit linebacker Chris Spielman was signed to fill the hole created by the departure of Bennett. It has been said that Spielman's signing had more than made up for the loss of Bennett and even though Spielman had become one of the Bills best run stuffers and inspirational leaders, nobody has since, replaced Cornelius Bennett's knack for turning the game around with one of his patented "big plays."