[3][4] Cooper stopped being affected by asthma prior to attending high school,[2] and he competed in American Junior Rodeo Association events, winning an award as "outstanding individual in 25 years" in 1977.
[4] In his rookie PRCA season, 1976, Cooper won the organization's tie-down roping championship and led the event in average earnings at the National Finals Rodeo (NFR).
[3] At the 1978 Cheyenne Frontier Days rodeo, he led all cowboys in prize money won, and his calf-roping winnings were the largest recorded in any non-NFR event at the time.
[6] After breaking one of his wrists the previous year,[7] Cooper won his second calf-roping season championship in 1980, and had a third-place NFR average earnings finish in the discipline.
However, he narrowly lost out on the PRCA's all-around season championship to his cousin, Jimmie Cooper, who earned $47.60 more in prize money than he did during 1981.
[7] He won his third consecutive PRCA tie-down roping championship, and fourth overall, in 1982, rallying from a prize money deficit of nearly $15,000 at the season-ending NFR.
[12] After holding the lead in the all-around standings late in the NFR, Cooper ended up in second place for the year, behind Dee Pickett.
[14] In steer roping, Cooper was unable to defend his 1983 championship title; he was in seventh place before a win in the discipline at the NFSR caused him to move up to fourth for the year.
[17] He won the Cheyenne Frontier Days rodeo's all-around title in 1989,[18] and by September 1990 was the PRCA's all-time leading money winner with career earnings of more than $1.1 million.
Cooper was in sixth place in the 1990 PRCA NFSR standings, before breaking his left wrist and suffering a concussion in an automobile accident.
"[3] Fellow cowboy Joe Beaver praised Cooper's consistency and ability to avoid errors and said, "At his prime, he had no competition.