After earning his degree in 1925, he became head coach at Washington High School in Milwaukee and continued for 22 seasons, compiling a 141–30–6 record (.814) through 1946.
[10][11] The franchise's third head coach, he had a 17–31 (.354) record in four years, with no post-season appearances, as the only scheduled playoff then was the NFL title game.
[14][15] Blackbourn drafted many future hall of famers, including Forrest Gregg, Bart Starr, Paul Hornung, Jim Taylor, Jerry Kramer, and Ray Nitschke.
Green Bay's first four picks in that draft are considered among the best by a team in league history; in addition to Taylor, Nitschke, and Kramer, consensus All-American linebacker Dan Currie was selected third overall.
After the dismissal by the Packers, Blackbourn became the head coach at Carroll College in Waukesha for a single season in 1958, and led the Pioneers to a 6–2 record.