Brennan is currently a showrunner on NCIS: Los Angeles and remained an executive producer of the original NCIS series before he stepped down from his role at the end of Season 11 with Brennan ultimately handing over the duties to Gary Glasberg so that Brennan could devote himself to being the full-time and permanent showrunner for NCIS: Los Angeles. In July 2016, it was announced that Brennan was stepping down as showrunner of NCIS: Los Angeles. He later handed the reins over to R. Scott Gemmill.
Brennan is currently a showrunner on NCIS: Los Angeles and remained an executive producer of the original NCIS series before he stepped down from his role at the end of Season 11 with Brennan ultimately handing over the duties to Gary Glasberg so that Brennan could devote himself to being the full-time and permanent showrunner for NCIS: Los Angeles. In July 2016, it was announced that Brennan was stepping down as showrunner of NCIS: Los Angeles. He later handed the reins over to R. Scott Gemmill.