He accompanied Nesmith and then-wife Phyllis Barbour to California to try their luck in the Los Angeles-area music scene.
When Nesmith was cast in The Monkees, he recruited London as his stand-in on the set, and when the originally-fictitious band began playing on their own recordings, London sometimes served as bassist, allowing Peter Tork to play keyboards, banjo, or another instrument.
London also co-wrote "Don't Call On Me" with Nesmith, which was featured on Pisces, Aquarius, Capricorn & Jones Ltd. and a second-season TV episode, and appeared in bit parts on the show.
In 1970, he and Nesmith, who had decided to leave the Monkees, formed a new group with pedal steel guitar ace Red Rhodes and drummer John Ware.
Years after the Monkees and the First National Band, London served as key grip on several different productions, including 48 Hrs., Who Will Love My Children?, The Karate Kid, Long Time Gone, and Hudson Hawk.