[1] Letscher got his first professional acting job with a role in The Tropic Pickle, during the second season of Jeff Daniels' Purple Rose Theatre Company in Chelsea, Michigan.

He appeared in the miniseries Jackie, Ethel, Joan: Women of Camelot and in the television films King of Texas, The Beach Boys: An American Family, When Billie Beat Bobby, and Stolen Innocence.

His performance in Good Morning, Miami led to him being cast in the lead in the film Straight-Jacket, opposite Carrie Preston, about a gay Hollywood actor forced to marry a beard in the 1950s.

Despite low ratings, the dramedy series had loyal fans and critical acclaim, earning it a second season which included a larger role for Letscher.

[7] He appeared in the 2013 films, Atom Egoyan's Devil's Knot (about The West Memphis Three) and Spike Jonze's comedy Her, opposite Amy Adams.

[10] In June 2007, Jeff Daniels' Purple Rose Theatre Company in Chelsea, Michigan, staged the world premiere of Letscher's original play Sea of Fools, a farce set in Joseph McCarthy-era Hollywood.

In 2009, his play Gaps in the Fossil Record was staged at the Pacific Resident Theater, then had its world premiere production at the Purple Rose Theatre in 2016.