Broadway Musical About Sexual Predator - Shlomo Carlebach

Eric Anderson in "Soul Doctor" at the New York Theater Workshop.

Wearing a bushy beard and the absent-minded expression of a father preoccupied with work at the dinner table, Eric Anderson, who plays the Jewish singer Shlomo Carlebach in the bio-musical “Soul Doctor,” appears smaller than life. That changes, however, when he starts to sing.

Transforming from a mild-mannered rabbi into a kinetic dynamo, he imbues his numbers with their own arc, often starting in a meditative mood before slowly building to a joyous, leaping roar. Mr. Anderson’s understated acting style pays off here, and his onstage performances are the best part of this otherwise safe, mechanical portrait of a fascinating cultural figure.

Carlebach, whose family escaped Nazi Germany and ended up in New York, where his father ran a small synagogue, was the rare Orthodox pop star. Gifted musically, he gravitated toward the New York folk club scene in the 1960s.

He mixed gospel and soul influences with traditional Jewish music. In the process he developed a following throughout the world for his sunny, spirited songs, particularly among the tie-dyed countercultural set. After a prolific career he died in 1994.

Written and directed by Daniel S. Wise, the show tracks this evolution during an overlong 2 hours 45 minutes, focusing on Carlebach’s struggle between the conservative religious world and the progressive music scene. In the first act he tries to persuade crowds to separate into male and female groups and does his best to avoid touching women, as is religious custom. But as he gains success, he embraces a new lifestyle.

And yet Carlebach continues preaching the virtues of the Torah; his flock includes a collective of hippies in San Francisco that he calls the House of Love and Prayer. In this telling, Nina Simone, played with lovely delicacy and strong voice by Erica Ash, proves to be a key inspiration at various points in his life; songs she made famous fill out the score, which is dominated by Carlebach’s own music. There’s even some romantic spark between them that goes insufficiently explored.

Mr. Wise creates the framework for a potentially fascinating show but doesn’t fill it in with the necessary psychology or personality to make his protagonist vivid. Carlebach remains a cipher.

A subplot about his marriage, which is shaken by his constant touring, is shoehorned into the story, but its thinness only underlines how little we learn about what motivates Carlebach. His critics, generally dogmatic religious types, are merely one-dimensional villains.

Even putting aside the show’s failure to explore some of the more controversial criticisms of Carlebach, like the report in Lilith Magazine, released after his death, that accused him of sexual harassment and abuse, this remains a gentle, sanitized portrait. It comes alive, however, when Mr. Anderson bursts into song. That’s when “Soul Doctor” stops treading carefully and begins to stomp.