Del Arco's breakout role came in 2003 when he landed a recurring guest star role on FX Networks' highly popular series "Nip/Tuck", where he played a transgender woman named Sofia Lopez. Roles on other highly rated shows such as "24", "The Sopranos", and "Dollhouse" followed. Beginning in 2007, Del Arco had a series regular role on TNT cable network's "The Closer" as the openly gay medical examiner, Dr. Morales. He continued the role in the series' spin-off, "Major Crimes". In 2014, he appeared in the episode "Love Sucks" of "The Crazy Ones", as the previously unseen husband of Brad Garrett's character.