Biography
He was born on October 23, 1964, in Santa Monica, California. Of Mexican descent.

After joining Suicidal Tendencies (in 1989), Robert brought a funky touch to the band's sound, which can be heard on the albums Lights...Camera...Revolution! and The Art of Rebellion. Eventually Rob infected Suicidal Tendencies leader Mike Muir with funk music and the two of them organized the Infectious Grooves project to play more funk-oriented music.

In the late nineties, Robert joins Ozzy Osbourne's band.

On February 24, 2003, Trujillo becomes the bassist for the band Metallica. Rob's audition process and acceptance into the band is shown in the documentary Some Kind of Monster.