Marin Alsop can be reserved or overly careful in some repertory, but she’s got Leonard Bernstein under her skin. (Dean Alexaner/Courtesy of Baltimore Symphony Orchestrar)

Marin Alsop studied with Leonard Bernstein. This could be dismissed as a mere PR bullet point, a seal of approval, an item on the checklist of her distinctions. Or so at least you might think, until you hear her conduct Bernstein’s music. Alsop can be reserved or overly careful in some repertory, but she’s got Bernstein under her skin. This is music full of bounce and nervous energy and self-aggrandizement and breast-beating, always looking over its shoulder to make sure you like it, and Alsop takes it lovingly in hand and shows it to advantage without letting it carry her away.

Her ability was clear when she led “Mass” with the Baltimore Symphony Orchestra in 2008 and made an uneven and misunderstood theater piece one of the highlights of her ongoing tenure as the BSO’s music director. But it was even more impressive Friday, when she and the orchestra performed at the Music Center at Strathmore and took on the problematic “Kaddish” symphony, helping this awkward, often embarrassing ugly duckling of a piece reveal its inner swan.

“Kaddish,” written in 1963 and Bernstein’s third and last symphony, raises some of the same questions of faith that “Mass” addressed eight years later. Its biggest problem is its text. It centers on a narrator talking to God in an overblown vernacular that evokes the tone and language of a TV sitcom, turned to seriousness instead of humor: imagine the Odd Couple engaged in religious debate. (God is addressed as “angry, wrinkled Old Majesty”; at another point, the narrator wishes he could take God in his arms and rock him to sleep.) It’s toe-curling stuff, and there have been various attempts to fix it. Bernstein’s daughter Jamie has written her own version of the text, as has Sam Pisar, a Holocaust survivor who was the narrator for the National Symphony Orchestra’s performance of the same work in June 2011.

I was perfectly willing to believe that the text was unusable — until I heard Alsop and the gifted actress Claire Bloom perform it. Their performance didn’t so much rehabilitate it as give it a context: This whole piece is dated, but it’s a unified whole, and text and music match better than you might think. Both are much lighter and less profound than they believe themselves to be. Bloom found just the right tone of gentle overblown anxiety, not quite petulant and not quite thundering, to make the words palatable, and the orchestra and Alsop further tempered them with some fine playing. Certainly it was a better performance than the National Symphony’s reading last year. The Washington Chorus and the Maryland State Boychoir offered articulate cohesion. One piece of continuity was the soprano Kelley Nassief, who was a little dwarfed here by her placement in the balcony above the huge forces on stage.

The symphony was by far the most compelling piece on the program. This was the BSO’s second all-American program in two weeks, a rousing start to the season that plays to the music director’s strengths, but the first half didn’t have the fizz and spark of the second. It opened with John Adams’s “Short Ride in a Fast Machine,” an energetic piece that’s taken its place in the orchestral canon. But here after a spicy beginning it turned bland, with more emphasis on long sustained brass notes than the rapid notes of strings and percussion, as if it had worked its way into a comfortable groove and could simply coast along.

This was followed by “Ansel Adams: America,” a piece by Dave and Chris Brubeck that the BSO gave its East Coast premiere in 2010. I applaud the orchestra’s instinct to revisit a new work so soon after its premiere, giving it a chance to become somewhat familiar to its audience. But the work itself held little interest for me, consisting of attractive but generic statements, repeated over and over, played under a compilation of photographs both of and by Adams. The juxtaposition of disparate images raised interesting but perhaps unintended questions about the dividing line between art and documentary — is the music supposed to accompany Adams’s art or narrate his life? Unfortunately, it also created the impression that this was less a musical work than a well-meaning educational slide show.