In the early 1930s, Ornstein gave his last public performance. A few years later, he and his wife—the former Pauline Cosio Mallet-Prèvost (1892–1985), also a pianist—founded the Ornstein School of Music in Philadelphia. Among the students there, John Coltrane and Jimmy Smith would go on to major careers in jazz. The Ornsteins directed and taught at the school until it closed with their retirement in 1953. They essentially disappeared from public view until the mid-1970s, when they were tracked down by music historian Vivian Perlis: the couple was spending the winter in a Texas trailer park (they also had a home in New Hampshire). Ornstein had continued to compose music; equipped with a powerful memory, he was not diligent about writing it all down and had not sought to publicize it for decades. Though his style had tempered greatly since the 1910s, it retained its unique character, and with his rediscovery came a new burst of productivity. In Gann's description, piano works composed by Ornstein in his eighties, such as "Solitude" and "Rendezvous at the Lake", featured melodies that "sprang through endless ornate curlicues that brought no other composer to mind."