"The good Lord has been very good to me well, to all of us in this room for a very long time," Underwood said after the win.
Underwood the top winner in CMT Awards history with 10 belt buckles, including four for video of the year also is celebrating the opening of a Country Music Hall of Fame exhibit and five years with the Grand Ole Opry. She'll also close down the Country Music Association Festival on Sunday night. All this comes less than two weeks after joining the Rolling Stones in Toronto on May 25 the eighth anniversary of her win on "American Idol."
The night belonged to Lambert and FGL before Underwood's flourish at the finish.
The duo of Tyler Hubbard and Brian Kelley won breakthrough video and duo video of the year on their breakthrough hit
"Cruise," then performed a remixed version of the song with rapper Nelly to close the show.
"This is a little overwhelming," Kelley said. "We've got the best fans in the world. You guys are freaking amazing."
The breezy, easy-grooving "Cruise" pushed the duo to country stardom last year. Their remix with Nelly moved into the top five on Billboard's Hot 100 pop songs list this week, making it the rare country crossover hit and an early candidate for song of the summer.
Lambert won female video of the year for "Mama's Broken Heart" and CMT performance video of the year for "Over You," recorded during the 2012 "CMT Artist of the Year" broadcast.
"I just got a kiss from Lenny Kravitz," Lambert said as she took the stage for her second trophy. "That was an award in itself."
Much of the early focus of the show was on country's biggest male star, Jason Aldean. Making his first appearance as an awards show co-host, he kicked off the show by playing "American Woman" with Kravitz, got hosting tips from an unlikely cast of characters that included Blake Shelton, Reba McEntire, Kelsey Grammer, Vince Vaughn, Lorraine Bracco and Luke Bryan.
He also won collaborative video of the year for "The Only Way I Know" with Bryan and Church, who were among the top nominees coming into the show with Lambert.
Lady Antebellum won group video of the year for "Downtown" and took the stage with mother-to-be Hillary Scott about a month from her due date.
"This is Hillary's maternity present coming early," Charles Kelley said.
Lambert's husband Blake Shelton won male video of the year for "Sure Be Cool If You Did"
an award presented by Lambert. Shelton was traveling due to his duties as a coach on TV's "The Voice," so Lambert accepted, shouting, "Honey, I'm drinking for two tonight."
The CMT Awards are rarely focused on winners of the belt buckle trophy and Wednesday night was no different.
Underwood had the most poignant moment of the night with "See You Again," her tribute to tornado victims in her home state. Swift had the night's most eye-catching performance, singing "Red" with a color guard of flag bearers while playing electric guitar and wearing a red-and-black shorts-and-overcoat ensemble that had a Sgt. Pepper feel to it.
Nicole Kidman with husband Keith Urban joined in as Darius Rucker and Lady Antebellum led the crowd at Bridgestone Arena in a "Wagon Wheel" sing-a-long. Hunter Hayes took it outside and walked through a crowd of hundreds before taking the stage, and Bryan performed across the street at Lower Broadway venue The Stage.