Kersh acts as an antagonist who bureaucratically prevents Special Agents Fox Mulder, Dana Scully, John Doggett and Monica Reyes from investigating cases dealing with the paranormal, dubbed X-Files.

The character has been met with mixed to negative critical responses, although he was initially positively received before coming to be considered a "one-note" role as the series progressed.

As an Assistant Director, he temporarily became supervisor to Agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) when they were assigned away from the X-Files division.

[4] When Mulder and Scully were reassigned to the X-Files office, Kersh continued to climb the ladder, culminating in an assignment as Deputy Director of the Federal Bureau of Investigation.

"[10] Michael Avalos, writing for the Knight Ridder Tribune, felt positively about the introduction of Kersh, saying he harbored "almost fond memories" of the former recurring character, Section Chief Scott Blevins, played by Charles Cioffi.

[14] George Avalos and Michael Liedtke from the Contra Costa Times reacted positive towards James Pickens, Jr.'s performance in the eighth season's "Via Negativa", saying the story "clicked" thanks to Kersh and Walter Skinner.

[16] Writing for Cinefantastique about the character's introduction, Paul Vitaris called Pickens "a fine addition to the cast" of the series, describing his portrayal of Kersh as "a strong presence".

[18] Robert Shearman and Lars Pearson, in their book Wanting to Believe: A Critical Guide to The X-Files, Millennium & The Lone Gunmen, describe Kersh's return in the eighth season as "contrived but forgivable".

[20] In 1999, Pickens was nominated for a Screen Actors Guild Award for Outstanding Performance by an Ensemble in a Drama Series for his work as Kersh, alongside Gillian Anderson, William B. Davis, David Duchovny, Mitch Pileggi and Chris Owens.