Dinah Was, by Oliver Goldstick, at the Merrimack Repertory Theatre, Lowell, through March 11. Starring Laiona Michelle, J. Bernard Calloway, Nadiyah S. Dorsey, John Kool, and W. T. Martin, with Julia Cook, John Kneeland, and Michael Morrison. Directed by Charles Towers; musical director e’Marcus Harper.

This was my first time at the Merrimack Repertory Theatre in Lowell, after years of listening to friends praise its productions. Judging from Dinah Was, which I saw in preview last Friday night, they were right. Dinah Was is a musical biopic of the life of R&B singer Dinah Washington, “Queen of the Blues,” a contemporary of Billie Holliday who lived a similarly fraught life and who died of an overdose in 1963 at the age of 39.

The story line is somewhat weak—flashbacks a little confusing; motivations formulaic and shallow; it’s a biopic, after all—but these drawbacks are more than compensated for by the performances and the music. Laiona Michelle is marvelous as Washington. The entire present of the play takes place in the lobby of the Sahara Hotel in Vegas, where Washington, drunk and high on pills, waits angrily, an embarrassment to management dressed only in her black slip, for the room she will never get. She can perform at the Sahara; in fact she’s the headliner; but she cannot eat in the hotel’s dining rooms, nor sleep in its guest rooms, nor swim in the pool, nor even gamble in its casino without a white man accompanying her. Among the many excuses put forth by management: she’s so popular and successful that the place is sold out—not a room to be had.

The many flashbacks give us Washington’s story—her disapproving and religious mother, her absent father, her many marriages, her addiction to diet pills, her driving ambition, her rising star as club performer and recording artist. It ends with her finally on stage at the Sahara, where she brings a terrified and excited kitchen worker up to the mike to sing with her. It’s the highlight of the play, and Nadiyah S. Dorsey’s performance as Violet is spectacular. She vibrates between stage fright, excitement, disbelief, and, ultimately, complete surrender to the song in a performance that could hold its own anywhere. Dorsey, like all the supporting actors in the play, holds down multiple roles: Violet; Washington’s sleek “executive assistant”; and Washington’s disapproving mother. Hard to believe it’s the same actress doing them all.

All the other actors, listed above, are outstanding in their various roles. But it’s the music—along with the quintet of musicians—that carries the story and makes the play: readers who have been around a little while will remember Washington’s renditions of “Stars Fell on Alabama,” “What a Difference a Day Makes,” “Come Rain or Come Shine,” among others. A little longer in the tooth? Maybe you recall the raunchy “Long John Blues.” Michelle may not quite be Dinah Washington, but she comes darned close, singing her way with verve and conviction through the repertoire.

This play is well worth the short trip up Interstate 495 to the MRT, which shares space in the huge Liberty Hall on Merrimack Street with, of all things, a boxing ring. Don’t ask.