After graduating from college, Riley was selected by the Bengals in the 6th round of the 1969 Common Draft. When Riley reported to training camp, Cincinnati head coachPaul Brown decided to convert Riley to the cornerback position. Brown's decision turned out to be a very good one. Riley made an immediate impact for the Bengals as a defensive back, recording 4 interceptions and 66 return yards. He also recovered 2 fumbles, added another 334 yards on 14 kickoff returns, and even caught 2 passes for 15 yards on offense. For the rest of his career, Riley established himself as one of the top defensive backs in Pro Football, recording 3 or more interceptions in all but 3 of his 15 seasons. His best season was in 1976, when he recorded 9 interceptions, 141 return yards, 1 touchdown, and 2 fumble recoveries. His 9 interceptions set a franchise record for most interceptions in one season, and would remain the team record for 30 years until it was broken by Deltha O'Neal in 2005. He also set a record that year by intercepting 3 passes in the final game of the season, a 42-3 win over New York Jets. Riley intercepted Richard Todd once and future Hall of Fame quarterback Joe Namath twice. It was Namath's final game as a New York Jet. Since then several Bengals' players have tied the record, including Riley, who did it again in a 1982 game, picking off 3 passes from Oakland Raiders quarterback Jim Plunkett, but nobody has broken it. But despite his success in the 1976 season, Riley was not selected to play in the Pro Bowl. Meanwhile, his defensive back teammate Lemar Parrish, who recorded just 2 interceptions and missed half the season with injuries, was a Pro Bowl selection. Riley continued to be an impact player for Cincinnati throughout the rest of his career. In 1981, he recorded 5 interceptions and 1 fumble recovery, assisting his team to their first ever Super Bowl appearance against the San Francisco 49ers in Super Bowl XVI. In his final NFL season, the 36-year-old Riley recorded 8 interceptions, 89 return yards, 2 touchdowns, and 2 fumble recoveries. In his 15 seasons in the NFL, Riley recorded a total of 65 interceptions, 596 return yards, 5 touchdowns, 18 fumble recoveries, 96 fumble return yards, 334 kickoff return yards, and 15 receiving yards. His interceptions, interception return yards, and interceptions returned for touchdowns are all Bengals' records.
Legacy
After his Pro Football playing career ended, Riley spent two years as an assistant coach for the Green Bay Packers. In 1986, he took over as the head coach of his alma mater, Florida A&M. Riley coached Florida A&M from 1986–1993, compiling a 48-39-2 record, with two Mid-Eastern Athletic Conference titles and 2 MEAC Coach of the Year awards. Riley then served as Florida A&M's athletic director from 1994-2003. He then retired and lived the rest of his life in his hometown of Bartow, Florida. Commenting about not yet being enshrined in the Hall of Fame, Riley said "I think my numbers are deserving of the Hall of Fame. I've always been a modest and low-key type guy. I've always thought your work would speak for you. It's like it's working against me now because the older you get and the longer you stay out of it, people forget who you are." Riley was a member of Alpha Phi Alpha fraternity. In 2007, he was named to the Florida High School Association All-Century Team which selected the Top 33 players in the 100-year history of high school football in the state of Florida's history.
Death
Riley died of a heart attack on June 7, 2020, at the age of 72.