Considering that his day job consists of helping other people make their own music – for nearly 50 years he’s been one of the busiest bass players in New York – the songs of Jay Leonhart are amazingly personal. Mr. Leonhart has launched what might be his most ambitious venture as a bandleader and star, taking his own trio (with trumpeter Michael Leonhart, and his son, pianist Ted Rosenthal) into the Metropolitan Room for a month of Wednesdays.

Writing from what lyricist Dory Previn referred to as the “subjective” rather than the “objective” point of view, Mr. Leonhart’s songs are primarily about the life of a musician. His set on opening night included no less than three songs about flying to gigs: one about sitting next to Leonard Bernstein coast to coast, one about nearly missing a show because of a storm, and another about how the airlines try to prevent you from flying with a full-sized contrabass to begin with. It’s not only the lyrics (like the one about being snubbed by Dizzy Gillespie), the music itself is full of unusual twists and turns that suggest a jazz improvisation, and full of chords that only jazz musicians know.

Overall, these songs are idiosyncratic in the best sense of the word, and are so full of wise and telling details (there’s one he didn’t include at the opening show about a German shepherd who treats his bass as if it were a tree, if you know what I mean) that he takes what is incredibly specific to him and virtually to him alone (I mean, Lenny Bernstein – really), and makes it seem almost universal – like a set of experiences that everyone can relate to.

Not all of his songs are about the musical experience: some are just random observations that he makes into musical essays, provocative think pieces that are sung rather than read on the printed page. There’s “Life in the Middle Ages” (“the plague is so contagious”) and one about a famous convict in his native Baltimore, who somehow managed to dig and escape through a 99-foot tunnel that later became a local landmark. Overall, so many are concerned with the difficulties of getting from Point A to Point B that it’s no surprise that Mr. Leonhart was recruited to play in and write songs for the off-Broadway revue, Secrets Every Smart Traveler Should Know. (He does include one tune about traveling on the Hindenberg which was deemed too much of a downer – literally – by the show’s producers.) Another airline-related aria describes about a clueless character engaged in trying to carry a laundry list of prohibited items through customs (including “killer bees and fire ants”) but can’t fathom “Why oh why are you detaining me?”

What makes Mr. Leonhart’s music so listenable overall is a compelling sense of irony, as when he writes his tenderest waltz melody for a song about a schizoid who’s convinced that the Martians – or someone – is “Coming to Get Me.” A profound sense of optimism reigns throughout: even when Mr. Leonhart makes a great show of complaining, like in the two songs of his that are probably the most “covered” by other performers, “Robert Frost” and “Beat My Dog,” there’s a deep sense of affection – like he gives you hints that he really doesn’t mean it when he starts griping about this or that. He even finds an upbeat message in the tale of his misanthropic, alcoholic “Uncle Jim.” Mr. Leonhart is also the master of the perfectly understated closing line: “Me and Lenny” ends with the plainly stated fact that after spending all that quality time with the legendary conductor, “Lenny hasn’t called me yet,” while “Uncle Jim” winds up touchingly with “And they named me after him.”