Mark A. Heimann is an American chess player and machine learning researcher.

[1] In October 2007, he was ranked as the national #2 under-14 player, only behind future grandmaster Marc Tyler Arnold.

[3] In December 2012, he played for Washington University St. Louis' "A" team in the Pan-American Intercollegiate Chess Championships, where he was the second-most successful player, recording 4 wins, 1 draw, and 1 loss.

[5] In November 2024, he scored a GM norm at the U.S. Masters Chess Championship.

He is a machine learning researcher at Lawrence Livermore National Laboratory.