Selected in the third round of the 1968 NFL Draft out of NAIA power Adams State, Don Cockroft arrived in Cleveland as a versatile specialist with a big leg. He immediately secured both kicking and punting duties as a rookie, launching a 13-year career spent entirely in orange and brown.

For his first nine seasons (1968–1976), Cockroft pulled rare double duty as the franchise’s full-time placekicker and punter. He excelled at both disciplines, combining directional placement on punts with accuracy on field goals. Though he was frequently overlooked for Pro Bowl honors, Cockroft was undeniably one of the league's top specialists, leading the NFL in Field Goal Percentage three times (1968, 1972, and 1974) and topping the league in Punting Yards in 1972.

Cockroft relinquished punting duties in 1977 to focus solely on placekicking for the final four years of his career. That move paid off during the iconic 1980 "Kardiac Kids" campaign, where his veteran presence and clutch late-game kicks helped propel Cleveland to the AFC Central title. His final professional action came during the 1980 divisional playoff game against Oakland, bringing a memorable close to a long career in Northeast Ohio.

Across 13 seasons in Cleveland (1968–1980), Cockroft appeared in 178 regular-season games, converting 216 field goals and 432 extra points for 1,080 total points, while also booming 651 punts for 26,262 yards. The team inducted him into the Cleveland Browns Legends in 2007.