Jake Heggie’s “It’s a Wonderful Life’’ is a high-flying operatic version of the Frank Capra film that has since its 1946 opening become a Christmas favorite.

If you remember the film as sentimental, it did have its sentimental moments, and Heggie and librettist Gene Scheer’s opera does too, but the music holds its own and manages to delve even more deeply into the dark side of the story with striking results.

The opera, in its West Coast premiere, was co-commissioned by San Francisco Opera, Houston Grand Opera, where it premiered in 2016, and the Indiana University School of Music.

The story is leaner, but the narrative is unchanged: George Bailey, doer of good deeds, desires to leave small-town New York, go to college and see the world, but is forced to remain in Bedford Falls in order to keep the family business afloat and hold the greedy Mr. Potter at bay.

The score is ebullient, diverse and fleshed out with winning music, especially for Clara, the second-class angel (she replaces the elderly, testy Clarence in the film) who more or less runs the show and saves George Bailey’s life when he becomes despondent over failed dreams.

There are buoyant choruses, a lively quartet for Clara’s fellows angels, dramatic duets, and lustrous love songs for George and Mary, childhood pals who marry and come to learn that life is good after all in Bedford Falls.

Patrick Summers, music director of Houston Grand Opera and major collaborator of Heggie’s (he has conducted every Heggie world premiere) draws an exuberant, detailed performance from the opera orchestra, and glorious singing abounds.

South African soprano Golda Schultz in her San Francisco debut portrays Clara with creamy tones and suave phrasing, and she takes the stage with a saucy, commanding presence.

Canadian soprano Andriana Chuchman, also in her company debut, is the silvery-toned Mary Hatch; her gleaming vocal high lines and vivacious dancing bring the scenes from Bailey’s young years to life. Tenor William Burden as George sings with vibrant colorings and complete engagement.

The character of the rich and heartless Mr. Potter is strikingly drawn. The Act 2 duet between Potter, potently sung by baritone Rod Gilfry, and George, in which Potter offers George a large sum of money if he will become Potter’s assistant, is a dramatic high point.

The Capra film, incidentally, was considered so incendiary — it was thought that it might inspire class warfare — that it was investigated by both the FBI and the House Un-American Activities Committee.

This scene in the opera is even more darkly sketched. Keith Jameson and Joshua Hopkins deliver excellent portrayals of Uncle Billy and George’s brother Harry, respectively. Patti LuPone has a cameo as a disembodied voice from heaven.

There are minor issues: Scheer’s libretto occasionally gets bogged down in literal detail and the use of spoken dialogue to illustrate a soulless world without George Bailey seems somewhat awkward, but the overall impression is one of a show with places to go.

Leonard Foglia’s staging is stellar, understated and clear, and the clever setting by Robert Brill, brightly lit by Brian Nason, shows the days of George Bailey’s life as numerous doors on which projections play.

Dazzling opening and ending scenes and snowy scrims capture the holiday spirit in a way that delighted the nearly full-house audience. San Francisco Opera may just have found its holiday party.

“It’s a Wonderful Life” has eight more performances at the War Memorial Opera House through Dec. 9 in San Francisco.