Post, setting school single-season records by throwing for 3,757 yards and 38 touchdowns, and single-game records by throwing for 614 yards, 35 completions, and seven touchdowns in a single game, and was named the Division II Player of the Year.

[8] In his junior season, Klein set the California state record by throwing for more than 5,000 yards, and was Los Angeles All-City Player of the Year.

[13][11] He then transferred to Carson High School for his senior season and helped the Colts win the 1988 City Section 4-A Division championship, as he was named California State Player of the Year, Parade Magazine High School All-America, and a Campbell Soup All-American.

[19][16][11][18][20] He passed for a 248/407 (60 percent) completion rate, was # 1 in Division II for total offense at a record 405.2 yards per game, was named an EC AC Div.

[22] Nonetheless, the Stevens Point Journal only projected him as a fifth-round choice and as the eighth-best quarterback in the draft.

As a fourth-round draftee by the Atlanta Falcons, he would actually prove the third quarterback drafted, behind first-rounders Heath Shuler and Trent Dilfer.

[11] In 1996, he was waived by the team and played with the Amsterdam Admirals in the World Football League, which would become NFL Europe.