Highsmith started his career with the Denver Broncos of the AFL, playing 23 games in 2 seasons. He next played with the Montreal Alouettes for 2 years and 22 games, winning the Grey Cup championship in 1970. He then headed to the Houston Oilers of the NFL for a 1-year and 9 -game stay. 1973 saw him back in Montreal, playing only 1 game. The Memphis Southmen of the new WFL called, and he played 2 seasons with them. He finished his career back in the CFL with the Toronto Argonauts, playing 21 games over 2 years.