William Kempner Stats & Bio | Marlins Pitcher

About William Kempner

William Kempner is a right-handed pitcher for the Miami Marlins, wearing jersey number 71. Standing at 6'0" and 222 lbs, the San Jose, California native brings a determined, competitive presence to the mound. Born on June 18, 2001, Kempner developed his skills at Gonzaga University before earning his opportunity at the professional level. The young hurler has made an impressive early statement in his MLB career, posting a flawless 0.0 ERA across two appearances while striking out three batters over two innings of work. His ability to keep opposing hitters off balance speaks to the refinement he built during his collegiate years. At just 23 years old, Kempner represents an exciting piece of Miami's pitching future, and fans will be eager to watch his continued development throughout the season.

Updated: Mar 17, 2026