He reached his tennis singles career high ranking of 174 on May 3, 2010.

[1] His first win on the ATP Tour came as a qualifier at the 2008 US Open[3] where he beat Olivier Rochus in five sets.

[4] He lost to Rafael Nadal in the next round, 1–6, 2–6, 4–6, despite taking a 3–0 lead in the third set.

DeHeart played college tennis at the University of Illinois at Urbana-Champaign, where he achieved a number one in the ITA singles rankings and was a two-time All-American.

As a junior, he won the ITA National Intercollegiate Indoor Singles Championship.