The Blank Space hitmaker, who went into the prizegiving with 14 nominations, took home one of the first awards of the night for Top Billboard 200 Album for her smash hit 1989.
She went on to receive prizes for Top Billboard 200 Artist, Top 100 Artist, Top Female Artist, Top Digital Songs Artist, Top Streaming Song (Video), and Billboard Chart Achievement Award before the final accolade of the night, Top Artist.
Swift also opened the show with the premiere of her all-action, star-studded new video Bad Blood, which featured cameos from the likes of Cindy Crawford, Jessica Alba, Lena Dunham, Ellie Goulding and Selena Gomez.
Her friend Sam Smith was the other big winner of the night, taking home the Top Male Artist, New Artist, and Top Radio Songs Artist prizes.
The British soul singer was unable to attend the event, as he's on strict vocal rest after undergoing throat surgery last week (14May15), but he did send a pre-taped video message, during which he held up cue cards with his acceptance speech written on it. It read: "First, Thank you Billboard for this incredible honour. Secondly thank you to my amazing fans. It's time like this that I realise how lucky I am to have you in my life. Can't wait to get this surgery out of the way so I can sing my a** off for you again.
"And lastly, seeing as you guys are in Vegas, Taylor... Put a 100 (dollar bill) on black for me. Nicki (Minaj)... Oh... My... God.. look at her bum! And Ed (Sheeran)... I've organised a special dance for you at... (male strip club) Chippendales. Good night and turn up!"
Other multiple winners included Pharrell Williams, who swept the three R&B categories and Iggy Azalea, who was also a triple winner, Hozier and One Direction.
Mariah Carey, who recently kicked off her Las Vegas residency at Caesars Palace, took the stage at the Billboards for the first time in 17 years and treated the audience with a performance of her number one hit Vision of Love and her latest song Infinity.
Actress Molly Ringwald celebrated the 30th anniversary of The Breakfast Club onstage as she introduced Simple Minds to the stage for a performance of their iconic hit from the movie, Don't You (Forget About Me), while other show highlights included performances by Van Halen, Ed Sheeran, Kanye West and the cast of hit U.S. hip-hop drama Empire.
Star-studded duets were also a theme throughout the night, as Meghan Trainor and John Legend, Little Big Town and Faith Hill, Chris Brown and Pitbull, David Guetta and Nicki Minaj, and Britney Spears and Iggy Azalea all took the stage for memorable performances.
Rapper Ludacris returned to host the prizegiving for the second year in a row, alongside Legend's wife and supermodel Chrissy Teigen at the MGM Grand Hotel & Casino.
The list of winners at the 2015 Billboard Music Awards is:
Top Artist - Taylor Swift
Top New Artist - Sam Smith
Top Male Artist - Sam Smith
Top Female Artist - Taylor Swift
Top Duo/Group - One Direction
Top Touring Artist - One Direction
Top Billboard 200 Artist - Taylor Swift
Top Billboard 200 Album - Taylor Swift, 1989
Top Hot 100 Artist - Taylor Swift
Top Hot 100 Song - Meghan Trainor, All About That Bass
Top Radio Songs Artist - Sam Smith
Top Radio Song - John Legend, All of Me
Top Digital Songs Artist - Taylor Swift
Top Digital Song - Meghan Trainor, All About That Bass
Top Social Artist - Justin Bieber
Top Streaming Artist - Iggy Azalea
Top Streaming Song (Audio) - John Legend, All of Me
Top Streaming Song (Video) - Taylor Swift, Shake It Off
Top Christian Artist - Hillsong United
Top Christian Song - Carrie Underwood, Something in the Water
Top Christian Album - Lecrae, Anomaly
Top Country Artist - Florida Georgia Line
Top Country Song - Jason Aldean, Burnin' It Down
Top Country Album - Jason Aldean, Old Boots, New Dirt
Top Dance/Electronic Artist - Calvin Harris
Top Dance/Electronic Song - DJ Snake & Lil Jon, Turn Down For What
Top Dance/Electronic Album - Lindsey Stirling, Shatter Me
Top Latin Artist - Romeo Santos
Top Latin Song - Enrique Iglesias feat. Descemer Bueno & Gente de Zona, Bailando
Top Latin Album - Enrique Iglesias, Sex and Love
Top R&B Artist - Pharrell Williams
Top R&B Song - Pharrell Williams, Happy
Top R&B Album - Pharrell Williams, G I R L
Top Rap Artist - Iggy Azalea
Top Rap Song - Iggy Azalea featuring Charli XCX, Fancy
Top Rap Album - J. Cole, 2014 Forest Hills Drive
Top Rock Artist - Hozier
Top Rock Song - Hozier, Take Me to Church
Top Rock Album - Coldplay, Ghost Stories
Top Soundtrack - Frozen
Billboard Chart Achievement Award - Taylor Swift
The Hollywood Reporter: Billboard Music Awards 2015 Finalists: The Complete List ...