The pianist here is Walter Hendl. At the time he was assistant conductor to the NYPO as well as a pianist. He later worked at the Eastman School and Julliard. He lived to about 90 and his obit surprisingly dwells on his alcoholism.

The pianist is Walter Hendl

I was curious who the pianist and the conductor of the NYP were on this recording. Through a Google search I reached the NYP's radiogoldindex.com website and found this entry that fits the recording you have on the Internet Archive. The date is January 6, 1946, the pianist is Walter Handle and the conductor is Artur Rodzinski. A Google search of Walter Handle resulted with no information at all. Strange! The CBS recording is from a scratchy record but Mr. Handles' performance of this concerto is good. Here is the information from HYP'sradiogoldindex.com website:

66991. The New York Philharmonic Symphony Orchestra. January 6, 1946. Program #130. CBS net. Sponsored by: U. S. Rubber. The program originates from Carnegie Hall. Beethoven's "Egmont Overture" and his Symphony #7. The intermission talk is by Frank W. Notestein (of Princeton University) who speaks about, "The Changing World Population." "The Piano Concerto In F" by George Gershwin. News bulletins: the Chinese Communists are to meet for a "Unity Conference" in Chun King, the U. N. O. General Assembly is to meet. The New York Philharmonic, Artur Rodzinski (conductor), Walter Handle (piano), Frank W. Notestein. 1:27:39. Audio condition: Excellent. Complete.