He played major junior with the Saskatoon Blades. Swift Current Broncos, and the Edmonton Oil Kings from 1967 to 1972. With Edmonton he scored 115 goals in just two seasons. The Los Angeles Kings picked him 20th overall in the 1972 NHL Amateur Draft. Kozak turned pro with the Kings in the 1972-73 season and stayed with them for six solid seasons. The Vancouver Canucks accquired him in 1978 but he spent most of the rest of his career in the minors. He retired in 1982. Kozak played in 437 NHL games, scoring 96 goals and 86 assists. In 29 playoff games, Kozak scored 7 goals and 2 assists.