The following year, he participated in the historic Ninth Street Art Exhibition, and subsequently taught at Pratt Institute along with Franz Kline, Adolph Gottlieb, Jack Tworkov, Philip Guston, Milton Resnick and Tony Smith.
In 1951 he began a long-term teaching position at the Pratt Institute, and Leo Castelli selected one of his works for the historic Ninth Street Show.
"[5] These paintings, often grand in size, attracted favorable reviews not only from Sandler, but also from such critics as Dore Ashton and Fairfield Porter, and author James A. Michener.
Porter wrote, "...Richenburg's painting...seems to be specifically about energy,"[6] while Ashton responded to the huge abstract canvases by observing that "His image of a pitch-black place cut through by flickering neon light is persistently urban and nocturnal.
"[8] Although Richenburg's career faltered with the advent of Pop Art and his relocation to Ithaca, New York (where he taught at Cornell University), it was a fortuitous visit in 1986 by Grad to Richenburg's studio in the Springs on Long Island, where he lived with his second wife, artist Margaret Kerr, that led to new appreciation of his art.