While with Wright, Smith worked with other apprentices on the Armstrong house in Ogden Dunes, Indiana, before deciding to strike out on his own in 1940. Despite his lack of formal architectural training or a license, he was commissioned to design and build several homes including studios for Theodoros Stamos, Betty Parsons and a sprawling compound for Fred Olsen. Despite these successes, the architect/client relationship frustrated Smith enough that he gravitated toward his artwork. Smith continued to paint in abstract geometric composition and found himself teaching a basic design course at Hunter College. One class assignment consisted of forming maquettes out of cigarette box cardboard, he then asked his students to increase the scale of their designs by 5 times with regular cardboard which startled students and teacher alike as powerful objects began to take shape. In 1956, while sitting in a colleague's office, he was drawn to the form of a simple file cabinet. He phoned a local fabricator and commissioned a box 2' x 3' x 2' in size. Although the welders assumed he was crazed, they treated the project with the utmost workmanship and the result was a stunning form to Smith. He had discovered a sculpting process that he continued to hone.
Smith was also a teacher in various institutions including New York University, Cooper Union, Pratt Institute, Bennington College, and Hunter College, where he mentored artists such as Pat Lipsky. He was a leading sculptor in the 1960s and 1970s, typically associated with the Minimal art movement. Smith was asked to anchor the seminal 1966 show at the Jewish Museum in New York entitled Primary Structures.
Smith was asked to teach a sculpture course at the University of Hawaii in Manoa during the summer of 1969. He designed two unrealized works, Haole Crater(a recessed garden) and Hubris but eventually created The Fourth Sign that was sited on the campus. His Hawaii experience also generated fodder for his "For..." series whose initials are friends and artists he met during his time in Manoa.Wikipedia