It took a new musical adaptation to bring Mark Harelik’s “The Immigrant” — one of the most- produced plays in the early 1990s — back to Arizona, in a fresh staging by Arizona Theatre Company.

The story of a Russian Jew who settles in tiny Hamilton, Texas, at the start of the 20th century, it’s a poignant piece for a region renowned for its immigrant population, and audience members at Herberger Theater Center buzzed with pre-show discussion about where they came from and the countries their families left to settle in America.

As a play, “The Immigrant” is a heartwarming masterpiece. As a new musical, it’s mediocre.

There’s a richness of humanity that pours from the play, drawn directly from the life story of playwright Harelik’s grandfather, Haskell Harelik (played here by Aaron Serotsky), who settled as the lone Jew in a Texas town that’s practically “To Kill a Mockingbird” small.

Despite his Yiddish tongue and position as a lowly traveling banana peddler, he’s taken in by a Christian couple, banker Milton Perry (Craig Spidle) and his wife, Ima (Hollis Resnik).

Over time, he establishes his own store in town and saves enough money to bring his wife, Leah (Ana Sferruzza), to America. She bristles at their new town, neither a temple nor Jew in sight, and Haskell’s kosher-free assimilation. Friendship between the families blossoms, though, and together they learn about compassion and understanding.

The actors, hired from New York and Chicago, all give powerful performances that respect and illuminate their characters beautifully.

But dramatic scenes punctuated by sharp moments of comedy (such as one in which Haskell outlines his Torah-inspired choices of names for his children — Mordecai, Moisha, etc. — to which the banker replies, “You’re going to give the Church of Christ the fits”) are woefully undercut by what feel like forced segues into song.

Music writer Steven Alper and lyricist Sarah Knapp have fused onto Harelik’s book the kind of tunes that could best be described as vestigial. Knapp makes trite lyrical choices and Alper’s mostly limp score adds about as much weight as designer Ralph Funicello’s sets — open walls and hanging windows, mere suggestions of homes and storefronts in Hamilton.

In sets, sparseness is invigorating; in musical theater scoring, it’s awkward.

It speaks to the power of “The Immigrant,” though, that it’s a remarkable and enjoyable piece — despite its score. I only hope ATC’s staging sparks other theater companies to take a new look at Harelik’s original play.