In 1983, Stapleton was signed by the Milwaukee Brewers as an amateur free agent. He began his professional career in 1984 in Milwaukee's minor league organization. With the Class-A Beloit Brewers that season, he went 9–6 with a 2.33 ERA in 48 games, all in relief. Milwaukee assigned Stapleton to the Stockton Ports of the Class-A California League in 1985. With the Ports, he compiled a 2–9 record with a 2.54 ERA in 52 relief appearances. Stapleton was promoted to the Double-A level in 1986. With the El Paso Diablos of the Texas League that year, he compiled a 6–2 record with a 3.15 ERA in 38 relief appearances. Stapleton started the 1987 season with the Double-A El Paso Diablos, where in four games he compiled a 1.74 ERA. He was soon promoted to the Triple-ADenver Bears. Stapleton went 11–3 with a 4.05 ERA, five saves and 74 strikeouts in 44 games, nine of which were starts. Of his nine starts, Stapleton went for a complete game in four and pitched a shutout in one. During the month of August with the Bears, Stapleton went a perfect 6–0. He was called up to the Milwaukee Brewers on September 14, 1987. He made his Major League Baseball debut that day, earning a win in 3 innings pitched against the New York Yankees. Stapleton finished the 1987 season with Milwaukee going 2–0 with a 1.84 ERA and 14 strikeouts in four games, all in relief. In January 1988, Stapleton re-signed with the Milwaukee Brewers. That year, he started the season in the major leagues. He made his season debut that year against the Boston Red Sox, pitching 1 innings, giving-up no runs on two hits. After just six games with the Brewers, Stapleton suffered a shoulder injury, which ended his season. In those games, he compiled no wins or losses with a 5.93 ERA and six strikeouts. Stapleton was removed from the Brewers 40-man roster after undergoing surgery on his injured shoulder. After the season, the Houston Astros selected him in the Rule 5 draft. In 1989, Stapleton played with the Houston Astros during spring training. Before the start of the regular season, the Astros returned Stapleton to the Milwaukee Brewers. After pitching in extended spring training, the Brewers assigned Stapleton to the Triple-A Denver Bears. He spent the entire season with Denver, going 2–6 with a 5.10 ERA, one save and 46 strikeouts in 34 games, 10 of which were starts.
Coaching career
In 2001, Stapleton was hired as the head baseball coach of his alma mater, Grand Canyon University. In 2002, he led the team to a 38–21 record. The school's baseball/softball complex, Stapleton-Pierson Stadium, is partially named after him. On March 10, 2011, Stapleton was dismissed. In February 2014, he was named manager of the Orem Owlz.
Personal
Stapleton resides in Chandler, Arizona with his wife, Patti and their children; Kadi and Dakota.