The honors were handed out in Nashville.
Brad Paisley, who won male vocalist, teared up as he thanked his father, who he said carried amplifiers and ran sound "even though he didn't know what he was doing." Paisley also won music video for his hit "Online."
Sugarland won vocal duo of the year, breaking Brooks & Dunn's long-standing lock on the award. Brooks & Dunn had won the duo category 14 of the last 15 years, including the last six in a row.
And 17-year-old Taylor Swift won the horizon award for newcomer.
Rascal Flatts won top vocal group, and George Strait took top album for "It Just Comes Natural." Underwood won single of the year for "Before He Cheats." Other winners included Jerry Douglas as musician of the year.