Shortly thereafter, he enrolled at the College of San Mateo, where he wrote charts for the community college's well-regarded big band and ascended to the first trumpet chair. (A snippet of tape of Lesh on trumpet at CSM can be heard on "Born Cross-Eyed" from the Grateful Dead's 1968 release "Anthem of the Sun".) After transferring with sophomore standing to the University of California, Berkeley in 1961, he befriended future Grateful Dead keyboardist Tom Constanten before dropping out again after less than a semester. At the behest of Constanten, he studied under the Italian modernist Luciano Berio in a graduate-level course at Mills College in the spring of 1962; their classmates included Steve Reich and Stanford University cross-registrant John Chowning. Lesh’s inborn intelligence and curiosity, coupled with his considerable involvement with learning institutions and esteemed mentors, later led to his being one of the decided intellectuals of the Grateful Dead.