David Stefanik is in his fourth season as an assistant coach for the Wisconsin Lutheran College men's and women's tennis programs.

Stefanik arrived at Wisconsin Lutheran after previously serving as head coach of the boys' tennis team at Cudahy High School in 2016. He has also held assistant coaching positions for the boys' tennis programs at Whitewater High School (2007-2008) and Middleton High School (2006).

Stefanik competed for four seasons (2004-2008) on the men's tennis team at UW-Whitewater, where he primarily played at No. 6 singles and No. 3 doubles. Serving as team captain his senior season, Stefanik compiled a career 28-9 singles record and a 33-13 doubles mark. He graduated from UWW in 2008 with a bachelor's degree in health, human performance, and recreation.

A two-time state qualifier in No. 1 singles at Oak Creek High School, Stefanik played four seasons for the Knights. 

Stefanik and his wife, Laura, live in Greendale with their daughter, Lucy. He is a fitness and tennis coach in the Greater Milwaukee area.