Dunn attended Robinson Secondary School in Fairfax, Virginia from 1984 to 1988 where he earned Washington Post All-Metropolitan Baseball honors in 1987 and 1988.

Dunn was a top 10 Baseball America magazine prospect in 1988, but had committed to the University of North Carolina at Chapel Hill prior to the 1988 amateur draft which resulted in his slide to the 4th round.

Both in 1994 and 1995 he hit over .300 for the Salt Lake Buzz of the Pacific Coast League, earning call-ups to Minnesota.

He made his major league debut on May 3, 1994, starting a game against the Milwaukee Brewers at County Stadium.

He played 92 games for the Buffalo Bisons of the American Association, but never again reached the major league level.