She was on faculty at the Juilliard School in New York City and provided master classes in piano performance at other conservatories including the American Conservatory of Music in Chicago during the 1970s in collaboration with William Browning, also a teacher of great repute. Of her playing in general, Jerome D. Bohm of the N.Y. Herald-Tribune wrote; "An innate musicality permeates all her interpretations and bears the stamp of her individuality."
Adele's performances included a Carnegie Hall recital on January 25, 1949, in which she played Scarlatti, Brahms, Schubert, Schumann, Scriabin, Rachmaninoff, Stravinsky and Chopin. She was 42.
Her students included: Edward Aldwell, Agustin Anievas, Tzimon Barto, Enrique Bátiz (later a conductor), Jeffrey Biegel, David Brunell, Anthony Byrne, Sergio Calligaris, Jeffrey Campbell, Alec Chien, José Carlos Cocarelli, Cy Coleman, Robert Chumbley, Robert Dennison, Stewart L. Gordon, Steven Graff, Horacio Gutiérrez, Jennifer Hayghe, Steven Heyman, Stephen Hough, Byron Janis, Ted Joselson, Leon Whitesell,Sonja Kim, Norman Krieger, Daniel Lessner, Stefan Lindgren, Panayis Lyras, Diana McIntosh, Beata Moon, Pascal Nemirovski, Edward Newman, Ken Noda, Peter Orth, Jon Kimura Parker, Pamela Mia Paul, Güher Pekinel and Süher Pekinel, Miguel Franz Pinto, Elisabeth Pridonoff, Jose Ramos-Santana, Santiago Rodriguez, Thomas Schumacher, Neil Sedaka, Jeffrey Swann, Emma Tahmizian, Ezequiel Viñao, Donald Walker, Donna Lee Weng, Rosa Torres-Pardo
Adele Marcus died on 3 May 1995 at her home in Manhattan. She was 89.
- Elder, Dean. "Adele Marcus: World-Class Teacher", Clavier, Vol. 22, No. 5, May-June, 1983.
- Kehler, George. The Piano in Concert, Scarecrow Press, 1982.
- Press, Jaques Cattell (Ed.). Who's who in American Music. Classical, First edition. R. R. Bowker, New York 1983.
- Sadie, Stanley; Hitchcock, H. Wiley (Ed.). The New Grove Dictionary of American Music. Grove's Dictionaries of Music, 1986.
- Holland, Bernard. Adele Marcus Is Dead at 89; Taught Many Notable Pianists, New York Times, 5 May 1995. (retrieved January 25, 2010)