The pop star, 21, was the second musical act to take the stage at Hollywood's Dolby Theatre for the fundraising telecast, which was broadcast on 36 U.S. networks, as well as in Canada and overseas.
Grande gave a pitch perfect performance of "My Everything," off her album of the same name. Earlier in the night, Dave Matthews Band played the song "Mercy," from their 2012 album Away from the World.
Before Grande sang her tender ballad for millions of television viewers, the former Sam & Cat star tweeted, "supporting a cause that is near & dear to my heart. tonight I'm singing for grandps! i miss u."