After earning his M.L.A. from Harvard’s Graduate School of Design in 1938, John Simonds joined his brother Philip, who was an engineer and landscape architect, in Pittsburgh and formed Simonds and Simonds in 1939. The firm, which started out specializing in local residential and garden design, grew to become a multidisciplinary planning firm practicing across the country. The brothers were joined by Lester Albertson Collins and were known as Collins, Simonds and Simonds from 1952 to 1970, after which they adopted their present moniker Environmental Planning and Design (EPD).
Simonds and Simonds contributed significantly to the reshaping of post-War Pittsburgh. Their design for Mellon Square, a Modernist garden plaza over a parking garage, pioneered rooftop gardens in the early 1950s. The firm also worked on designs for Allegheny Commons and the Pittsburgh Aviary-Conservatory. John Simonds led the firm's work on the master plan of the 300-acre Chicago Botanic Garden beginning in 1963; it opened to the public in 1972. The partners accepted commissions on projects including educational and corporate campuses, urban renewal, and park planning. In the 1970s, EPD broadened their focus again to include master planning for highways, industrial parks, and housing communities. Their designs are recognized for balancing environmental concerns with community-based planning concepts.