AND ON THE 8TH DAY, GOD MADE THE B-3:

Beneath his black turban, above his long white beard, Dr. Lonnie Smith's eyes grew large and his grin wide earlier this month at Manhattan's Jazz Standard. It was his 70th birthday, which he celebrated by doing what he's done for nearly a half-century: Building and then deconstructing hard-swinging grooves; reveling in the sonic possibilities of a Hammond B-3 organ; surprising listeners and bandmates with sudden rhythmic and dynamic shifts; and easing into ballads with disarming sweetness and absorbing soul. The listeners who packed the room traced Mr. Smith's moods, growing silent at some points and erupting with applause and even laughter at others. [...]

He found his true calling at a local music store where he'd sit until closing time most afternoons, he said. "One day the owner, Art Kubera, asked what I was doing. I told him, 'Sir, if I had an instrument, I could make a living.'" In particular, he coveted a Hammond B-3 organ. That evening he went home with the organ in the back of his brother's pickup truck, a gift from Kubera. "But I still had to figure out how to play that beast," he said.

He was a quick study, and his career ascended just as fast. Within months, he was performing in local clubs. He sat in one night at the Pine Grill with members of organist Jack McDuff's group, which featured Mr. Benson. He and Mr. Benson felt an instant connection. Around that same time, he passed up a chance to record with guitarist Grant Green, a heady opportunity for any young musician. "I hadn't been playing a good year then," he said. "I wasn't ready."

Several months later, when Mr. Benson needed an organist, Mr. Smith jumped at the chance. He played on Mr. Benson's 1966 Columbia debut; Mr. Benson returned the favor on "Finger Lickin' Good." Even then, Mr. Smith's playing sounded radical. "I really was thinking Jimmy Smith," he said of his early hero, "but it just always came out different."

Both he and Mr. Benson attained greater visibility after playing on "Alligator Boogaloo," alto saxophonist Lou Donaldson's 1967 surprise hit album for Blue Note. "The groove in that group was so automatic," Mr. Smith said. "It felt like we'd been doing it forever." Between 1968 and 1970, he had four successful Blue Note releases of his own.

Mr. Smith, who won't discuss precisely what his turban signifies, easily grows animated in conversation about nearly anything else and exudes a childlike wonder. He's the same way onstage. Drummer Herlin Riley, who played on Mr. Smith's brilliant 2009 CD "Rise Up!" said, "Lonnie's playing is so free, it liberates you if you can let go."

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