Swift, who also won awards for album of the year for "Fearless" and the best female vocalist of the year, is the first female solo artist to win the entertainer of the year category since 1999, when Shania Twain took home the prize.
Swift won all four awards for which she was nominated, making history on a historic night that included Darius Rucker's win as new artist.
"I'll never forget this moment because in this moment everything that I have ever wanted has just happened to me," Swift said through tears as she accepted the association's highest honor during ceremonies at Sommet Center.
Photos: Best Smiles in Country Music
Photos: 2009 CMA Red Carpet
Photos: CMA Awards Highlights
Photos: Country Squared
Photos: Winners' Circle
The 19-year-old crossover sensation beat the biggest names in country and snapped Kenny Chesney's stranglehold on the category: He won three straight and four of the last five. She also ended Carrie Underwood's three-year dominance in the female vocalist category.
Chesney hugged and kissed Swift on the cheek, then whispered a message in her ear before she received the trophy. She called her band on stage and was the center of a group hug as fans cheered wildly, holding signs that said, "We love you, Taylor"; her father cried in the audience.
"Every single person in that category let me open up for them this year," Swift said. "Thank you all so much. I love you."
Rucker was also a fan favorite, running into the crowd during his performance of "Alright." The Hootie and the Blowfish frontman, who has sold 1 million copies of his first country album, "Learn to Live," became the second African-American to win a major individual CMA.
He joins Charley Pride, who won entertainer of the year in 1971 and male vocalist in 1971-72.
"First of all, to the fans, thank y'all for accepting me," the jubilant Rucker said. "And I think most importantly, to country radio, you took a chance on a pop singer from Charleston, S.C. Thank you so much for that!"
Swift also won album of the year for "Fearless," the top-selling CD of the year, and video of the year for "Love Story."
"You guys, this album is my diary and so to all the people who voted for me for this is a thank you for saying you love my diary because that's the nicest compliment," Swift said.
Complete list of Winners
Photos: Taylor Swift
Brad Paisley, who led all nominees with seven, won two awards, including his third straight male vocalist of the year.
"This was the best time I've ever had at an awards show," said Paisley.
Lady Antebellum also won two awards, for vocal group and single of the year. The win in the vocal group category ended Rascal Flatts' six-year dominance.
"Rascal Flatts, you've inspired us for such a long time," Lady Antebellum singer Charles Kelly said. "Thank you so much for letting us be up here."
Jamey Johnson, along with James Otto and Lee Thomas Miller, won song of the year for "In Color."
"I never thought you guys would even let me come to things like this," Johnson, the country outlaw with the scruffy beard, joked as the audience laughed.
Swift kicked off the show with a playful version of her song, "Forever & Again," throwing a chair off a raised podium, sliding down a pole and dropping to her knees to the delighted cheers of the crowd.
It was the Zac Brown Band that set the room on fire, though, with its high-rev version of Charlie Daniels' "The Devil Went Down to Georgia."
Co-hosts Paisley and Underwood opened the show with a few new songs of their own, skewering Kanye West for his interruption of Swift's MTV Video Music Awards win - "Mama don't let your babies grow up to be Kanye" - and lamenting the break up of Brooks & Dunn.
Later in the show, telecast on ABC, country novelty singer Little Jimmy Dickens interrupted Paisley after Underwood told him that "Welcome to the Future" was one her favorite videos.
"Excuse me sir, excuse me. I'll let you finish later. Now, Brad Paisley, I know you had a nice video, but ... Taylor Swift made the best video in her time. You go girl," the diminutive Dickens said, goofing on West, who famously took the stage during Swift's acceptance speech to say that Beyonce deserved Swift's prize.
Brooks & Dunn, the best-selling duo who announced their split earlier this year, teamed with ZZ Top guitarist Billy Gibbons on a scorching version of "Honky Tonk Stomp" in what was billed as their last performance at show.
But CMA voters weren't moved by sentiment in the vocal duo of the year category, awarding Sugarland the honor for the third straight year.
"We don't usually expect this but we obviously didn't this year," said Jennifer Nettles, half of the duo that extended an invitation to Kix Brooks and Ronnie Dunn to come up and speak to their fans, but they declined.
"Well, I will say thank you for what you've done for us, thank you for what you've done for country music," Nettles said before leaving the stage.
Several tributes were paid to veterans with the show falling on Veterans Day. Underwood saluted service members and Randy Houser wore a POW/MIA hat among other nods.