After guest starring in an array of projects, Holtz appeared in the parody film "Vampires Suck" as Alex. His big break was the series "Make it or Break It," where he played Austin. Then he was back on the big screen as Chris in "The Perks of Being a Wallflower," in which Ezra Miller gave one of their best performances. 

His next big role was that of Richie Gecko in "From Dusk 'Til Dawn: The Series." playing a character that was originated by Quentin Tarantino in 1996's "From Dusk 'Til Dawn," a movie you may not realize was turned into a TV show. Regardless, Holtz managed to stand out and make the character of Richie his own.

From there, he popped up as K.O. Kelly in the CW's one-season take on "Katy Keene." That led to two additional appearances as K.O. on "Riverdale." He has since appeared in a wide variety of TV movies, big screen features and guest spots, including the Ben Affleck vehicle "Hypnotic." It looks like he has a reliable recurring home on "NCIS," even if he doesn't get to pop up that often.