In early April I was checking out the first performances at the new Blue LLama jazz club. Walking in one evening, I heard singer Allan Harris working through “Moody’s Mood for Love,” with lyrics by Eddie Jefferson, set to a classic modern jazz 1949 solo by saxophonist James Moody.

Some things are best left alone: to my mind, this song belonged to Moody, who performed it for decades. My first thought was of a fabulous evening some years ago when the master sang and played it at the Kerrytown Concert House. But such contemplation left me in an instant as Harris’s robust and sincere musicianship hooked me and pulled me in.

Harris rendered the song as it should be, without any gimmicks, but extended it beyond the original: he went on to expand, bend, and explore it in true jazz fashion, making it his own as I have never heard anyone else do. I stayed the rest of the evening, mesmerized by a true jazz vocalist.

“Moody’s Mood” is what is known as vocalese, words set to famous instrumental solos. I expected the singer to continue with other examples, but Harris moved on to ballads, blues, renditions of pop songs, and, surprisingly, to an amazing composition of his own, “Blue Was Angry.” A selection from his musical Cross That River, it tells a story about a runaway slave who became a cowboy. This is not just entertainment: Harris creates complex sets that explore music, history, and emotion in a manner that is all his own.

Harris grew up in Harlem in a family of musicians, meeting many of the greats of the African American jazz and entertainment worlds. One of his aunts ran a soul food place frequented by stars of the day: jazz lovers will recall the cover of Jimmy Smith’s classic Blue Note album, Home Cookin’, taken in front of the restaurant. Another aunt was linked to the famed pianist, composer, and publisher Clarence Williams, who recorded many great jazz sides in the twenties and thirties, using musicians such as Louis Armstrong, King Oliver, and Bessie Smith. Williams mentored the young Harris, instilling an appreciation of the deep history of jazz and the blues. Later, Harris was taken under the wing of singer Tony Bennett, who inspired him to move beyond entertainment to become a true artist.

Harris has a supple baritone voice with a nice rasp, a perfect sense of pitch, and the rhythmic suppleness of a jazz player. His repertoire seems endless: the ballads often have a touch of Nat King Cole, the blues run deep, and he always tells stories that make us feel and think. He will return to the Blue LLama on September 13 and 14.