Harry Connick Jr. was humbled by the turnout at Wolf Trap Sunday night, as any young musician in his right mind would be. Seven thousand people jammed the Filene Center and lawn, making the concert one of the biggest pop draws of the season.

Still, the 22-year-old New Orleans pianist and singer wasn't so humbled that he failed to muster the cool assurance of a big-band crooner. On the contrary, there were times when he was cocksure -- not exactly a sin if one of your models is Frank Sinatra and you don't want to appear entirely miscast fronting a 15-piece band.

As a singer, Connick was quick to give fans of his work on the best-selling "When Harry Met Sally" soundtrack what they came to hear -- alternately sentimental and sly readings of "It Had to Be You" and "Don't Get Around Much Anymore." Mixed in were new songs that displayed his considerable gifts as a tunesmith as well. Connick said he wrote some of these songs for "Dick Tracy," but that "Madonna shot them down." If the exuberant Johnny Mercer-like "Recipe for Love" is any indication of their caliber, it's the film's loss.

But most of Connick's finest moments came when he focused on his lifelong infatuation with New Orleans jazz and R&B piano traditions, working out knotty rhythms and harmonies in small group and big-band settings, and when he generously showcased his own trio and a fiery horn section brimming with talent.

Opening was a quartet led by the 20-year-old alto player Christopher Hollyday. A protege of jazz master Jackie McLean, Hollyday hardly had a chance to warm up during the 30-minute set, but he played standards and original tunes with a hard-bop drive and agility that belied his years.