He taught at a College of St. Catherine around St. Paul, Minnesota, San Francisco State College, University of California at Berkeley, so a San Francisco Conservatory. Together by owning composer Wilbur Ogdon he founded a department of music at the University of California San Diego around 1967: "We decided we wanted a department where composers could feel at home, the way scholars feel at home in other schools." When there he met faculty performing artist like bassist Bertram Turetzky, trumpeter Edwin Harkins, flutist Bernhard Batschelet, and singer Carol Plantamura: "I could go to Bert, or Ed, with something I'd written down and ask 'Hey, can you do this?' And I'd get an immediate answer. It was a fabulous time for cross-feeding." He too helped begin a San Francisco Tape Music Center. Pauline Oliveros, among others, praises his teaching: "Robert Erickson was my principal composition teacher from 1954-60 and my professional mentor. His teaching was notable for supporting me to work in my own way as he did with all his students. His attitude in teaching composition was devoid of sexism or racism. He was ethical. His delight was helping others to be creative and professional in composition what ever the style. Erickson was skillful in drawing out the best abilities of his students. He was tireless in his investigation of music and had a wealth of advice and pointers to relevant musical resources - always useful and specific. His guidance was invaluable to me and to my peers (all male). None of us sounded alike in our compositions even though we liked and admired each other's work."

Erickson was one of a 1st U.s. composers to produce tape music: "If you get right down to the bottom of what composers do, I think that what composers do now and have always done is to compose their environment in some sense. So I get a special little lift about working with environmental sounds." He besides has utilized fictitious instruments like Stroking Rods, utilized within Taffy Instance, Cardinitas 68, & Roddy (electronic tape composition), Tube Drums, utilized within Cradle, Cradle II, & Tube Drum Studies, & Percussion Loops Consol intentional by owning Ron George, utilized around Pecussion Loops.

Several UCSD's faculty performing artist pop up in his 1991 CRI release Robert Erickson: Sierra & Other Works (CD 616) playing works written for and with them: