Police procedurals and medical dramas have been milking the power of spinoffs and crossovers for decades, especially in the “One Chicago” franchise. While sharing actors within the franchise isn’t a new thing, one particular actor from “Chicago Med” has featured in the most episodes of the firefighting saga “Chicago Fire.”

As IMDb points out, Nick Gehlfuss, who plays an attending physician known as Dr. Will Halstead in the franchise, is the "Chicago Med" actor who appears in the most episodes of "Chicago Fire," credited as starring in 20 of them at the time of this writing. His first appearance comes courtesy of the Season 3 episode entitled "I Am the Apocalypse," which is the backdoor pilot for the "Chicago Med" spinoff.

Since joining the "One Chicago" franchise in 2015, Gehlfuss has remained a regular fixture. The "Chicago Med" alumnus has also lent his talents to "Chicago P.D." throughout the years, showing up in 17 episodes of the cop drama between 2015 and 2020.