Her four-song set opened with the anthemic "We Can't Stop," where people onstage were dressed in flower, mushroom and rainbow costumes. She gyrated and slapped a dwarf-sized dancer's butt onstage. She followed the colorful performance with "Party In the USA."
But it was her emotional rendition of "Wrecking Ball" that was her set's highlight. Cyrus' mascara was running as she left the stage after the song and the performance comes days after she announced she was no longer engaged to actor Liam Hemsworth. She thanked the audience for helping the song top the Billboard Hot 100 chart this week.
"I couldn't have done it without all you guys," she said.
Cyrus broke a record when she debuted the song's provocative video, which features her in the nude.
The wild child singer said she knows "things I'm doing that's getting me into trouble and it's just me doing what my heart and soul is telling me what to do."
Everything she's done is "inspired by the music," she said.
Cyrus, who will release her new album "Bangerz" next month, also sang a new song called "Look at What They've Done to My Song." The guitar tune featured lyrics like "They think I'm half insane."
Jason Derulo, Avril Lavigne, The Wanted and others also performed during the day. Paul McCartney, Maroon 5, Justin Timberlake and Tim McGraw took the stage Saturday night.