Signing with the Milwaukee Brewers organization in time for the 2003 campaign, Kieschnick returned to the majors in the role of pitcher/utility outfielder/DH. During the 2003 season, Kieschnick became the first player in the MLB to hit home runs as a pitcher, designated hitter, and pinch hitter in the same season. Throughout and , the Milwaukee Brewers took advantage of Kieschnick's versatility, using him as a pinch hitter, designated hitter, and left fielder in addition to his primary role in the bullpen. Kieschnick played three complete games as a left fielder in September 2003; these would be his only on-field appearances as a defensive player for Milwaukee (outside of his role as pitcher) during 2003-04.