Farrar is the bass guitar player for the American rock band Phantom Planet. He also joined a band called Operation Aloha with members of Gomez and Maroon 5. He and his wife Stephanie have started their own music project, called Bubble and Strife. Currently, he is touring with Maroon 5 – as an additional band member – on guitars, occasionally on the bass guitar, backing vocals, turntables and providing samples and other special effects (using the MPC). He also co-wrote and co-produced a few of the band's songs on all of their studio albums and remixed one of their songs, which is called "Woman", on Call and Response: The Remix Album, released in 2008. On August 31, 2012 – 11 a show in Argentina on the Overexposed World Tour – Sam filled-in for Mickey Madden on the bass guitar for the very first time – he subsequently filled-in for Mickey on the next few shows of the tour.
His father, John Farrar, was a member of The Shadows and also carved a successful songwriting career, penning many of Olivia Newton-John's big hits. His mother, Pat Carroll, was a successful Australian pop singer in the 1960s. He attended The Buckley School. Sam is married to Stephanie Eitel, formerly a member of the band Agent Sparks. Their daughter Vesper Pearl Farrar was born in August 2009.