Theater-goers can get fresh insight into Judy Garland — not to mention enjoy a thoroughly entertaining experience — when they see the new musical “Chasing Rainbows: The Road to Oz” at the Goodspeed Opera House.

Tina Marie Casamento Libby, who conceived “Chasing Rainbows,” was inspired by something Garland herself had said: that the history of her life was in her songs. So the tunes are culled from those that Garland sang. David Libby, Casamento Libby’s husband, adapted them, creating rich, distinctive versions that work together beautifully in the show. The songs are not only captivating, but they fit the storyline as if they were written specifically for it.

Casamento Libby’s other genius idea: focusing on Garland’s early years, so the tale ends when the then-16-year-old films “The Wizard of Oz.” Garland’s struggles over the course of her life after that point are well documented, but her pre-“Oz” existence is ripe for exploration. With Casamento Libby’s idea, Libby’s musical adaptation, Tyne Rafaeli’s direction, and Marc Acito’s smart, agile script, “Chasing Rainbows” bristles with energy and imagination. You can see why Goodspeed decided to stage this new piece on its mainstage, which is usually devoted to revivals; it’s a big, engaging show.

The show begins when Garland is a child named Frances Gumm, singing alongside her older sisters in a family stage act. Her parents are loving to their children, but the marriage is starting to fray, in part because of father Frank Gumm’s dicey financial decisions; one of the early scenes shows the family being escorted out of town by the local police.

They move to Hollywood with dreams that, at first, decidedly don’t come true. Little Frances, dubbed the little girl with the big voice, remains driven to get an MGM contract so she can help her family.

What she faces in Hollywood, though, is not easy. The executives criticize, with casual cruelty, her looks — her nose, her teeth, but, most of all, her weight.

Eventually, though, even sexist movie honchos can’t deny her talent. Frances, renamed Judy Garland, is begrudgingly given the role of Dorothy in “The Wizard of Oz,” and, as they say, a star is born.

What shines through any difficult times portrayed in “Chasing Rainbows” is Judy’s spirit. And a musical about a young Judy Garland lives or dies on how good an actress is playing the legend. This production is blessed with Ruby Rakos. (She takes over as the teen Judy early in the show from the younger but just-as-effective Ella Briggs.) She resembles Garland — the pert nose, the open-faced beauty, the wide-eyed expressiveness — and she nails the physical imitation; she scrunches her face like young Judy and captures Garland’s stance and how she held her arms when singing. More important, though, she conveys the teenage Judy’s essence — bubbling with a guilelessness but also indicating a great depth. While not aiming for a strict Garland imitation, she sings with the star’s nuance and preternatural artistry. Just two of the highlights: she finds the filigree beauty in “Over the Rainbow,” and she romps joyfully through “Got a Pair of New Shoes.”

The first act of “Chasing Rainbows” is phenomenal. It moves energetically but allows time for the script and the actors to build emotional moments. The songs make quite an impact, and the performers capture the heart of every tune and every scene.

The second act is solid but doesn’t quite live up to the first. There aren’t as many songs that make an indelible impression. Some of the dialogue and scenes feel a little rushed and abbreviated, as if they’d undergone a few too many cuts. Even so, “Rainbow’s” second half makes an impact, especially as it details Garland’s growth and eventual triumph.

When it comes to performers, boy, does this production have a deep bench.

As Judy’s father, Kevin Earley makes the most of his multifaceted role. Frank Gumm is a dreamer, perpetually getting his family into dire straits. Earley’s Frank charms Judy (and the audience) with his gentle humor and playfulness. But Earley gets under Frank’s skin, too, finding the character’s inner turmoil, which I won’t reveal any more about here. His performance of the song “I’m Always Chasing Rainbows” is downright gut-wrenching.

Sally Wilfert ably reflects the struggles that loving stage mother Ethel Gumm faces. When she duets with Earley on a bittersweet version of “You Made Me Love You,” she exposes just how torn Ethel feels about her relationship with Frank.

Portraying studio head Louis B. Mayer and his savvy secretary, Michael McCormick and Karen Mason are so good, they deserve their own separate show. Their characters get some of the funniest lines in the show, but, even beyond that, the actors bring sly comic stylings and performance pizzazz to the roles.

George Milner gets to display his range, portraying both the old-school comic George Jessel and the Southern-charmer pianist-composer Roger Edens.

Michael Wartella doesn’t look much like Mickey Rooney, but his energy and humor certainly match the star’s.

Not everything works. For instance, the few times when a bevy of characters from Garland’s life wander around her, as if in a movie montage providing a peek into her psyche, almost feel like parodies.

But so much does, in fact, work, down to the simple sets, which cleverly reconfigure to create everything from the modest Gumm home to an “Andy Hardy” set (scenic design is by Kristen Robinson), and the costumes designed by Elizabeth Caitlin Ward, especially the glamorous Hollywood gowns.

Best of all, “Chasing Rainbows” does Judy Garland proud.

If you go

What: “Chasing Rainbows: The Road to Oz”

Where: Goodspeed Opera House, 6 Main St., East Haddam

When: Through Nov. 27; 2 and 7:30 p.m. Wed., 7:30 p.m. Thurs., 8 p.m. Fri., 3 and 8 p.m. Sat., and 2 p.m. Sun.; also 2 p.m. some Thursdays and 6:30 p.m. some Sundays

Tickets: Start at $29

Contact: (860) 873-8668, goodspeed.org