Green was drafted by the Cardinals in the fourth round of the 1979 NFL Draft. He starred as a rookie returning kicks, including a 106-yard return for a touchdown against the Dallas Cowboys, tying an NFL record. Green also played well at cornerback. In 1981, he stepped in as wide receiver part-time and managed to gain 708 yards on merely 33 catches - nearly 21.5 yards per catch. The following season, Green fully transitioned to wide receiver and performed well in the strike-shortened season. Green truly shined during the next several seasons, particularly in 1984 when his 1,555 receiving yards were then the third highest in a season (through the 2005 season, this has since dropped to eighteenth). Green led the Cardinals in receiving in 1983, 1984 and 1988 (during those intervening years, veterans Pat Tilley and J. T. Smith split time leading the team in receiving).
Following a pair of decent seasons in 1989-90, Green was traded to the Cleveland Browns in 1991. The Browns elected to release Green before the regular season began, and he was subsequently signed to the Eagles, who sought veteran leadership at wide receiver to replace the retired Mike Quick and the waived Cris Carter. Green played much of that season, in which a lackluster offense was balanced by a sensational defense. Green played sparingly the following season and retired in 1993. John Madden honored Green in his annual All-Madden Team, stating that at one point, he regarded Green as not the best wide receiver in the game, but the best player. Green finished with 559 receptions for 8,965 yards and 66 touchdowns. He also rushed for 140 yards, returned 27 punts for 230 yards, and added another 2,002 yards on kickoff returns. He also intercepted 4 passes for 54 yards, and recovered 20 fumbles. Overall, he gained 11,391 yards and scored 69 touchdowns.
Since being retired from the NFL, Roy Green has shifted his focus to helping improve the health of current and former professional athletes through promoting sleep apnea awareness across the country. He has teamed up with dental icon, David Gergen, and a company called Pro Player Health Alliance to hold free public awareness events in local communities all over the nation. After joining the cause of Pro Player Health Alliance and using his extensive amount of connections to players, he has helped get over 150 former players successfully treated for sleep apnea.