Rob has been in many bands. Before Metallica he was the bassist for the Band Suicidal Tendencies which has a song featured in Skate 2. He has also worked with Jerry Cantrell, Black Label Society, Infectious Grooves, Glenn Tipton, Mass Mental, and Ozzy Osbourne. As a result of working with so many groups, Rob is experienced in many different genres, including hardcore punk, heavy metal, thrash metal, funk metal, and even grunge.
Rob plays bass mainly by plucking with his fingers, although he does occasionally use a pick (As far as previous Metallica bassists, Jason Newsted played with a pick most of the time, while Cliff Burton exclusively used his fingers). Another main feature in Rob's playing is using bass-slapping techniques.
One of Rob's signature moves on stage is to spin around in place a few times, creating a windmill effect. In fact, Rob recorded this move with mo-cap in order for it to appear in the game Guitar Hero: Metallica.
After the leaving of Bassist Jason Newsted, Metallica had auditions for a new Bassist for their CD St. Anger. Rob won the spot and has been touring and making music with Metallica ever since. He recently released Death Magnetic with the Band back in 2008. He is currently touring with Metallica for the Death Magnetic Tour.