Mio attended Colorado College from 1972 to 76. During that time, he established himself as a standout, winning first- and second-team all-star awards and making the NCAA West first all-American team two years in a row.
With the Racers, Mio's goaltending was rough, but the most meaningful event of his career occurred when he met his lifelong friend, Wayne Gretzky. Shortly after their meeting, Mio was part of the trade that sent Gretzky (along with Peter Driscoll) to the Edmonton Oilers on November 2, 1978.[1]
When the Oilers moved to the NHL for the 1979–80 season, Mio got his first NHL action, part of the young, highly talented lineup that included Gretzky, Mark Messier, Kevin Lowe, Glenn Anderson and Paul Coffey. Mio had his first winning season in 1980–81 before being traded to the New York Rangers.
In New York, Mio backstopped the Rangers for two seasons before rounding out his career with the Detroit Red Wings in 1985–86.
