After the war, while still convalescing, he began studies at the University of California, Berkeley, where he received his undergraduate and doctoral degrees in anthropology.
Meighan was hired as an instructor in anthropology at the University of California, Los Angeles in 1952 and continued at UCLA until his retirement in 1991.
He founded UCLA's Archaeological Survey, chaired its anthropology department, and played key roles in several regional and national organizations.
His fieldwork was widely dispersed, including stints throughout various parts of California and in Utah, Arizona, Baja California, western and central Mexico, Belize, Costa Rica, Chile, Guam, Nubia, and Syria.
In his later years, he advocated for retention of archaeological collections on merit of their scientific value, a perspective that has been hotly contested since his passing.