Missouri native Heneghan received his B. Arch from Washington University in St. Louis in 1962. In the 1960s, he worked in Fritz Benedict’s office along with childhood friend Dan Gale, with whom he formed a firm from 1966-1969. The last year of their partnership was busy. They designed the Hannah Dustin commercial building (300 S. Spring), the Aspen Interfaith Chapel of the Prince of Peace on Meadowood Drive, and the Cottonwoods Condominium, as well as residences for the Guggenheim and Horowitz families. Heneghan left Aspen to establish his practice in Hawaii.