Donahue was a starter on the 1975 and 1976 offensive lines that produced both of the games in which Michigan had three rushers accumulate 100 yards.
In May 2011, Donahue was inducted into the Chicago Catholic League Hall of Fame.
In September 2012, Donahue was inducted into the Chicagoland Sports Hall of Fame. 
Donahue was selected in the 11th round of the 1978 NFL Draft by the Cincinnati Bengals. He played offensive guard for the Bengals in 1978 and 1979. Donahue later recalled: "It was fun playing a couple of years with the Bengals. It was a great experience lining up against legends like Randy White of the Dallas Cowboys and Joe Greene and the Pittsburgh Steelers. The first time you're in a stance against them, you're almost too excited to hit them. You get over that real quick when you realize there is no hesitancy at all on their part on hitting you hard."