In 2014, Gehlfuss had a recurring role as Robbie Pratt in the fourth season of the Showtime comedy-drama Shameless. In 2015, he guest-starred in the penultimate episode of the short-lived NBC horror drama Constantine. Later that year, Gehlfuss was cast in the NBC medical drama Chicago Med as Dr. Will Halstead. Halstead was first introduced in the police procedural drama Chicago P.D. and afterwards, the drama Chicago Fire's backdoor pilot for Chicago Med.
On May 13, 2016, Gehlfuss married hotel marketer Lilian Matsuda.
