In 1941, with the support of the American Guild for German Cultural Freedom, he received a visa from the US Consulate; in May 1941 he left on the S.S. Capitain Paul Lemerle, reportedly the last ship allowed by the British to pass through the Straits of Gibraltar.
Throughout the 1950s and early 1960s, Heidenreich exhibited regularly, his work was widely collected, and he made significant contributions to Abstract Expressionism, both as a painter and watercolorist.
A significant number of artworks left behind in Heidenreich's New York studio have been cared for by family friends and collectors, primarily Richard M. Buxbaum and Emanuel Wolf, who have maintained the artist's legacy through continued exhibitions and publications.
In 2004, Heidenreich’s work was shown along with his teacher’s (Hans Hofmann) at a major exhibition at the Berkeley Art Museum/Pacific Film Archive, which published a catalog with essays by Peter Selz, Alla Efimova, and Gabriele Saure.
In 2006, the Goethe Institut in New York presented a retrospective of Heidenreich’s American work; in 2011 a major exhibit was mounted at the Pankow/Berlin Artists' Collective Gallery.
The Carl Heidenreich Foundation, established in 2015, supports exhibits of his work at US and European museums, as well as continuing research and a virtual catalogue raisonée on www.carlheidenreichfoundation.org.