Phil Woosnam, a Welsh professional soccer player who became the commissioner of the North American Soccer League in 1969 and held that post until 1983, helping to raise the sport’s profile in the United States, died on Friday in Marietta, Ga. He was 80.

The cause was advanced prostate cancer and Alzheimer’s disease, said his wife, Ruth.

A physics and mathematics teacher, Woosnam played amateur soccer with a number of teams in Wales and England before turning pro in 1958. He moved to the United States in 1966, lured by the promise of a new start in soccer in a country largely lukewarm to the world’s game. He was hired as the coach of the Atlanta Chiefs of the fledgling N.A.S.L. but could not resist a chance to get back on the field; in 1967, he scored the first goal in the first soccer game in Atlanta’s Fulton County Stadium.

Woosnam was named the league’s coach of the year in 1968. That year, he also coached the United States national team.

He became the commissioner of the league in 1969, when it had only five teams, and presided over its growth to 24 teams across the United States and Canada in 1980.