Alejandro also appeared in the movie Crossing Over, which was released in February 2009, alongside Harrison Ford. He played Detective Nate Moretta in Southland, produced by Emmy Award winner John Wells. Southland was canceled by NBC Broadcasting, just two weeks prior to the première of the show’s sophomore run, but has since been picked up by the cable network TNT.

In 2011, he appeared in the movie Red State, opposite John Goodman and directed by Kevin Smith, as well a horror film called Cassadaga. He also played Tony Arroyo, a homicide detective in the 2013 television show, Golden Boy. Alejandro portrayed Sheriff Tommy Solano in the ABC / A&E series The Returned.

In 2013, Alejandro joined the DC Comics-produced CW series Arrow, as the villainous Brother Blood. He recurred throughout the show’s second season. In January 2016, he began his role on the Fox TV series Lucifer as LAPD Homicide Detective Dan Espinoza.