Acquired from the Los Angeles Rams in 1962, Frank Ryan came to Cleveland with a reputation as a brainy, talented backup waiting for an opportunity. Over four seasons in L.A., Ryan had flashed potential, but the Rams' decision to draft Roman Gabriel made him expendable. Cleveland traded for him, initially envisioning him as depth behind starter Jim Ninowski.

An injury to Ninowski midway through the 1962 season pushed Ryan into the starting huddle. He seized the job and never gave it back, developing into one of the most effective and efficient signal-callers of the 1960s. Armed with a doctorate in mathematics from Rice University—earning him the nickname "Dr. Frank"—Ryan brought an analytical sharpness to Paul Brown's and Blanton Collier's offenses, blending cerebral pre-snap reads with a deep, accurate throwing arm.

In 1964, Ryan achieved the pinnacle of his career, leading the NFL with 25 touchdown passes in the regular season, which helped Cleveland finish 10-3-1 and reach the NFL Championship Game. During the final against the favored Baltimore Colts, Ryan delivered a masterful performance, throwing three second-half touchdown passes to Gary Collins, resulting in an unexpected 27-0 shutout victory. This championship marked a high point of the era, making Ryan the second—and to this day, the last—quarterback to guide the Cleveland Browns to a league title, after Otto Graham.

He maintained his high level of play over the next several seasons, earning three consecutive Pro Bowl selections from 1964 to 1966. In 1966, Ryan again led the league in touchdown passes, throwing a career-high 29 touchdowns against just 14 interceptions—a remarkable ratio for an era defined by aggressive downfield passing and tough defensive-coverage rules.

A series of nagging injuries, including severe shoulder and knee issues, began to limit his availability toward the end of the decade, prompting his departure from Cleveland after the 1968 season. He spent his final three years as a backup in Washington before retiring in 1971.

As a Brown, Ryan compiled a 52-22-2 record as a starter, throwing for 13,361 yards, 134 touchdowns, and 88 interceptions. The organization officially named him a Cleveland Browns Legend in 2005.