Brian F. O'Byrne stars as Ken Karn on the NBC drama "Aquarius."

O'Byrne starred opposite Kate Winslet in his Emmy Award-nominated role in "Mildred Pierce." His recent television credits include "Mercy Street," "The Magicians," "Saints & Strangers," "The Last Ship," "Prime Suspect," "FlashForward," "Brotherhood" and the acclaimed Irish series "Love/Hate."

O'Byrne's film credits include the critically acclaimed film "Million Dollar Baby," "Medeas," "Before the Devil Knows You're Dead," "Brooklyn's Finest" and "The International." He also starred in "Jimmy's Hall" and "Queen & Country," both of which premiered at the 2014 Cannes Film Festival.

O'Byrne was last seen on Broadway starring in "Outside Mullingar" at Manhattan Theatre Club. His other theater credits include "If There Is I Haven't Found It Yet," "The Coast of Utopia," "Doubt," "Shining City," "Frozen," "Lonesome West," "Beauty Queen of Leenane" and "Bedbound," in addition to his work with the inspiring "Theater of War." He has five Tony nominations, five Drama Desk nominations and has been awarded Obie, Lucille Lortel, and Outer Critics Circle awards, among others.

O'Byrne was trained at the Samuel Beckett Centre at Trinity College Dublin and raised in Mullagh, County Cavan.