Swift won Sunday night's top honor, giving her a leading four trophies as fans celebrated the women of pop music.
Swift didn't perform, but she was a constant presence on stage and the camera alighted on her as she danced to stars like Kendrick Lamar and Luke Bryan. Her win came after Katy Perry dazzled with her show-opening performance, Lady Gaga found another inventive way to grab your attention, Rihanna starred with her mother and Miley Cyrus closed performances with the assistance of a giant lip-syncing CGI kitty on her song "Wrecking Ball."
"I'm really out of breath," Swift said after taking the stage in a sequined mini-dress. "I was really going hard with the 'Wrecking Ball' thing."
The 23-year-old pop star also won country album of the year for "Red" and favorite female country and pop/rock artist.
"'Red' is very different than any album I've made before and the reason I was able to do that was because of the fans," Swift said. "I cannot believe what you've done in the last year. This album came out almost exactly a year ago and the fact that 6 million of you went out and bought it is crazy."
Justin Timberlake was next with three wins. One Direction and Macklemore & Ryan Lewis won two awards and Rihanna was given the AMA's first Icon Award to go with her win as favorite soul/R&B female artist.
Rihanna and her mother took center stage midway through the show when Monica Fenty presented her pop star daughter with the first Icon Award at the Nokia Theatre in Los Angeles. "Can we talk about how cute Rihanna's mom is?" Justin Timberlake asked while accepting one of his three awards, before affecting a Caribbean accent. "She's so proud of the Icon. I am too, Rihanna, I love you."
Fenty told Rihanna how proud she was of her daughter's success, saying, "I know the journey in your career has not always been an easy one."
"Just about 20 years ago is when I really started making your life a living hell with my annoying little husky man voice, you would call it," Rihanna said. "And I mean just disrupting the entire neighborhood. Westbury Road, Barbados, they could tell you that's the truth. I annoyed every one of my neighbors."
She performed "Diamonds" with an orchestra and took favorite soul/R&B female artist. Timberlake won soul/R&B album, soul/R&B male artist and pop/rock male artist.
Nickelodeon star Ariana Grande was named favorite new artist, Florida Georgia Line won single of the year for "Cruise" with Nelly in something of a surprise, Luke Bryan won favorite male country artist, and favorite rap/hip-hop act Macklemore & Ryan Lewis used their rap/hip-hop album acceptance speech to send a message of tolerance.
Ben Haggerty, the rapper known as Macklemore, accepted the award for favorite rap/hip-hop album, then quoted Martin Luther King Jr. in a live satellite feed from the rap group's latest tour stop.
"Due to the fact that we are in Florida tonight accepting this award I want to acknowledge Trayvon Martin and the hundreds and hundreds of kids each year that are dying due to racial profiling and the violence that follows it," he said. "This is really happening. These are our friends, our neighbors, our peers and our fans, and it's time that we look out for the youth and fight against racism and the laws that protect it."
Florida became a focal point after Martin's killer was freed under the state's stand your ground law. It was the first win of the night for Macklemore and Lewis, whose album "The Heist" has been an unexpected hit and made them the AMA's top nominees with six.
Katy Perry opened the show looking like a princess out of a classic Japanese painting. Dressed in a traditional Japanese dress, Perry's show-starting performance of "Unconditionally" included dozens of colorfully clad dancers waved fans, shadow danced in front of rice-paper screens and played the drums.
Perry was the early focus of the awards show, held at the Nokia Theatre in Los Angeles, arriving on the red carpet in a black strapless dress to screams from hundreds of fans. She said before the show she wanted to up her game, given the chance to open, and the whirling stage production was a wash of colors and movements before Perry disappeared in a puff of smoke.
One Direction was at times drowned out by screams during an understated performance of "Story of My Life." The decibel level was that way from the moment the British boy band arrived on the carpet, all smiles and dapper suits. Harry Styles stopped to take a picture with three fans.
Timberlake strapped on an acoustic guitar and played a soulfully raucous version of "Drink You Away." Macklemore crowd surfed on "Can't Hold Us." Jennifer Lopez absolutely nailed the elaborate dance numbers during her tribute to Salsa queen Celia Cruz, taking two dozen dancers through their paces while wearing a shimmering silver dress.
She winked at the crowd as she finished the number, the dancers sprawled around her on the floor.
Lady Gaga and R. Kelly put on an elaborate production for their song "Do What U Want," staging a presidential affair. Kelly played the president and Gaga a Marilyn Monroe-like mistress. Kelly gazed upward as Gaga table-danced on his desk, then stormed off the stage as an actor playing a reporter chased him asking about the affair.
And Cyrus shut things down with a performance that wasn't quite as over the top as her previous appearances this year but is likely to be talked about just as much. The camera stayed on Cyrus and the lip-syncing tabby throughout, and the cat ended the song by winking and sticking out its tongue - Cyrus' signature move.
Associated Press writer Jessica Herndon in Los Angeles contributed to this report.