He attended Franklin High School (Reisterstown, Maryland) located in Baltimore County, where he was a star pitcher on the baseball team.

[3] He also played amateur baseball as a young teen for legendary Baltimore coach Sterling "Sheriff" Fowble, who coached other future major leaguers such as Hall of Fame player Al Kaline and Ron Swoboda.

[4] He is one of a handful of major league players from Baltimore County to play in the World Series.

[9] On April 12, 1978, Haas struck out 14 New York Yankees, including Reggie Jackson 4 times, breaking the record for strikeouts in a single game for the Brewers.

[3] Haas spent the first ten seasons of his career in Milwaukee before being traded to the Oakland Athletics in 1986 for Steve Kiefer, Charlie O'Brien and two minor league players, where he played the final two years of his career, retiring in 1987.