 Seith began his professional career with Burnley, whom he joined in 1948 aged 16.He made his debut for the "Clarets" in 1953, in a 2–1 away victory against Manchester United, and soon became their regular right half.By 1959–60 Burnley had become a genuine title challenger and Seith played 27 games in that league campaign as they moved towards their first championship since 1920–21.