Hawking said in remarks delivered from the stage that he was "proud to have played a small role in this great story" of science.
The gala included appearances by actor and science aficionado Alan Alda, Broadway stars and cellist Yo-Yo Ma.
Hawking is best known for his work explaining the physics of black holes. In the 1960s, Hawking developed a degenerative disease that has impaired his ability to move and speak.
He uses an electronic speech synthesizer to communicate.