Kings of Leon rule before an audience

The three brothers of Kings of Leon went from low church to no church.

As their now legendary biography has it, Caleb, Nathan and Jared Followill soaked up classic rock on the car radio while driving with their father, an itinerant Pentecostal preacher. Eventually the temptations of skirt-chasing, whiskey and rock ‘n’ roll proved irresistible, and so the native Tennesseans, along with guitarist cousin Matthew, moved to Nashville and landed a record deal before they ever played a note in public.

What emerged is a very crafty hybrid — hillbilly new wave, you could call it — nursed into being by producers Ethan Johns (who has a blood connection, through his recording engineer father Glyn Johns, to the old sound) and Angelo, an inveterate Nashville songwriter.

While its origins are less than organic, Kings of Leon is growing into the bubba-rock part. The Kings’ 2003 debut, “Youth and Young Manhood,” had an appropriately raunchy atmosphere, but the songs were sometimes slight. The band’s sophomore album, “Aha Shake Heartbreak,” released last week, is better; it’s grow-on-you good, unpredictable in groove and cumulatively strong in punch.

But Kings of Leon is one of those bands that truly must be seen to be loved. As Brian Eno said of U2, the Kings make the most of their strengths and their limitations. For an hour at a sold-out 9:30 Club Saturday night, the band’s limitations — singer and rhythm-guitarist Caleb’s dirty-old-man growl; Matthew’s boxed-in guitar solos — suddenly seemed like the raw materials of a grand old rock show.

As famous for their shaggy fashion sense as for their music, the Kings in person didn’t overemphasize the mad-and-bad Southern Gothicism pose, as their records might lead to expect. The quartet could have been rehearsing in its suburban Nashville garage, for all its laid-back demeanor Saturday.

Yet no one could mistake the Kings’ casualness for a lack of belly fire.

Anchored by the rhythm section of Nathan and bassist Jared, the Kings can play with tightly coiled fury, as on the nail-spitting, Led Zeppelin-inspired “Pistol of Fire,” and with front-porch ease, as on the rural-squalor tale of “Trani.”

Where “Milk” is a boring, impenetrable slog on record (“She has problems with drinking milk and being school tardy/She’ll loan you her toothbrush, she’ll bartend your party” — say what?), in concert it became electric and dangerous, even sexy.

What the band lacks in chops, it makes up in idiosyncratic arrangements. After “Slow Night, So Long” crashed home from Nathan’s Keith Moon-like finale, the Kings tacked on an unfinished tango, in which Caleb taunts a “gold-diggin’ mama.” “King of the Rodeo” never finds its way out of a circular, intertwining guitar riff, but its “let the good times roll” chorus still manages to deliver a cool rush before Caleb winds the song up with stabs of “good time to roll on.”

Speaking of good times, wide exposure awaits Kings of Leon. The band has an appearance on “The Late Show with David Letterman” behind it and a couple of opening dates with U2 ahead of it. It already has a stake in the ground across the Atlantic, with more than 2 million sales in the United Kingdom. Add to that major-label support, fashion-mag write-ups and swooning critics.

Good time to roll on indeed.