How do you know when a band has arrived? Million-selling disc, sold-out arena show, top-selling ring tone? Kentucky juggernaut My Morning Jacket climbed a lofty peak when they joined the Boston Pops orchestra and conductor Keith Lockhart for two concerts at Boston’s storied Symphony Hall.

“This is a dream come true,” Jim James, MMJ’s shaggy-haired front man, gushed near the end of his band’s fifty-five-minute set with the Pops Thursday night. When Lockhart approached the band about collaborating earlier this year, James was humbled and stunned. But ultimately, the decision to accept Lockhart’s invitation was a no-brainer.

If James and company were spooked, they masked their emotions behind game faces. A relentless touring act, MMJ were as commanding and ferocious at Symphony Hall as they were playing to adoring acolytes at Bonnaroo and opening for Pearl Jam and Wilco.

Decked in tuxedoes, MMJ took the stage to an auditorium packed with their fans and Pops season-ticket holders, many of them blue-haired and pressed neatly into thousand-dollar suits. MMJ slipped comfortably into first gear with the acoustic serenade, “At Dawn.” James strummed a chiming acoustic guitar, while guitarist Carl Broemel coaxed a mournful theme from his pedal steel with the Pops jabbing and feinting gently in the background.

Unusually understated for a ninety-person ensemble, the Pops employed color and nuance and left most of the thunder to the band. MMJ is no bucking, one-trick pony though. While they can pummel stone into dust, the band also can transform a rebel yell to a whisper and deliver gorgeous, pensive ballads.

The band wore heartache on their sleeves during an ethereal “Just One Thing” and “Golden,” which featured James chucking a bluegrass rhythm as Broemel repeatedly wrung the melody from his pedal steel until it dissipated into an eerie silence. “I Will Sing You Songs,” laced with lyrical bitterness and pain, showcased James’ precious, quavering tenor. Unfolding tenderly, the tune roared to a bombastic conclusion courtesy of a Pops-conspired crescendo.

MMJ didn’t disappoint when it came to rock chops. “Gideon,” which the band played with the Pops two weeks ago on Letterman, was a driving, early set gem. “Wordless Chorus,” featured throbbing, electronica keyboards, reggae-inflected beats, and histrionic scatting by James.

The set closed with the aptly named “Run Thru.” Broemel, armed with the tune’s piercing signature lick, displayed a scorched-earth fury that was bolstered by the Pops’ rib-cage rattling accompaniment and Patrick Hallahan’s powerful drumming. Neil Young and Crazy Horse would have smiled with approval. The Pops’ late iconic maestro, Arthur Fiedler, however, may be rolling in his grave. Nonetheless, give the Pops credit for assembling an engaging night of music and reaching out to their next generation of fans. After the concert, Boston-bred The Slip played an hour-plus show in the stately Higginson Room in the basement of Symphony Hall. James and some of his cohorts bopped and swayed to The Slip’s latest musical vision, which emphasized vocals and song craft over the jazzy, instrumental improvisations they favored earlier in their career.