“Ragtime The Musical” is an epic, ambitious spectacle — a joy to hear because of its stellar lead players, gorgeous to see due to its costume splendor — about a tumultuous and contentious era of America’s past.

It’s an opportune musical journey that elevates the high-water mark of creative excellence for Diamond Head Theatre, as it launches its 103rd season.

Set in 1906, “Ragtime” depicts three overlapping storylines, involving a wealthy Waspish family from New Rochelle, a Jewish immigrant from Latvia settling in the Lower East Side with his daughter, and a prolific Harlem black musician riding a wave of a new musical style amid civil rights issues. The grand, robust opening number — with the three elements intersecting each other in exquisite dances — sets the template for the ensuing scenes.

Certainly, it’s a complex, fascinating quilt work of political power, immigration tussles, social injustices between the wealthy and the poor, ugly racial prejudice and even romance. The turn-of-the-last-century framework resonates with the forces and fractures that could have come straight from today’s headlines.

“Ragtime” features a book by Terrence McNally (he also did “The Full Monty,” if you can believe it), music by Stephen Flaherty, and lyrics by Lynn Ahrens. It’s based on a 1975 novel by E.L. Doctorow and the 1981 film adaptation by Milos Forman.

The title refers to the lilting black-originated new music of the era, popularized in real life by Scott Joplin and exemplified in the leading character, Coalhouse Walker Jr.

Roles large and small are plentiful, but the key players are the musician Coalhouse, originally portrayed by Brian Stokes Mitchell, and Sarah the servant, originally played by Audra McDonald. “Ragtime” enabled both to become Broadway legends, with McDonald earning a Tony for Best Featured Actress in a Musical (Mitchell was nominated).

It’s understandable that DHT imported two New Yorkers, Kent Overshown and Lindsay Roberts, to portray Coalhouse and Sarah, respectively. His powerful voice and energetic dancing, and her luminous and rapturous pipes, reflect professionalism that surely inspired the cast. Their “Wheels of a Dream” duet is riveting, impossible to forget.

John Rampage, director and co-choreographer (with Celia Chun), was tasked with moving 37 players in a series of engaging ensemble scenes, some dark and serious, others bright and humorous.

Emma Goldman (played by Lisa Konove) is an anarchist who was a force in the rise of socialism; hers is a stunning voice of dissent. More stellar sparks in the ranks: Mother (Lea Woods Almanza), who discovers an abandoned black baby (an out-of-wedlock child of Coalhouse and Sarah) in her New Rochelle garden and commits to raising the child despite Father’s (Garrett Hols) heartless stance; Tateh (Eli K.M. Foster), the enterprising immigrant from Latvia who transforms from a silhouette-cutting artist to filmmaker, realizing his American dream; Evelyn Nesbit (Terrace Althouse), a vaudeville trouper whose husband is a murderer in a “Crime of the Century” moment a la O.J. Simpson.

Amid the fictional profiles, real personalities of the era appear: Harry Houdini (Michael Nowicki), Booker T. Washington (Curtis Dunkin), J.P. Morgan (Shane Noel) and Henry Ford (LeGrand Tolo Lawrence).

“Ragtime” was a seesawing Broadway hit in two separate runs, premiering in 1998 and revived in 2009 in a more modest version. Its formal debut was in 1996 as a Canadian spectacle produced by Livent Inc. and its controversial but inventive impresario, Garth Drabinsky; he had a vision for bigness and greatness and rebuilt the Ford Centre for the Performing Arts in Toronto (since renamed the Toronto Centre for the Arts) and the similarly named Ford Center for Performing Arts in New York City (now the Lyric Theatre), to properly launch “Ragtime.” I saw that extravagant original Canadian version, and also the first version on Broadway, with bells and whistles like a drivable Model T Ford and fireworks.

DHT delivers the aura and fervor on a lesser scale. Costumer Karen G. Wolfe deserves hurrahs for the gamut of garbs (207 costumes) and Friston S. Ho‘okano designed all the hairpieces with era-appropriate styles.

Sets by Willie Sabel are simple but functional, with several home and door-front pieces and one gigantic postcard to Atlantic City. Phil Hidalgo conducts an orchestra of 10, large by DHT standards, and renders atmospheric, lilting ragtime piano riffs.