Musician Pegi Young, Neil’s ex-wife, who died on New Year’s Day, co-founded a school for children with special needs

Pegi Young, who died on New Year’s Day at the age of 66, was a singer-songwriter, a rock star’s muse and the catalyst behind the Bridge School, a private organization based in Northern California for children with severe speech and physical impairments. Ms. Young, diagnosed with uterine cancer in the fall of 2017, was known for her free spirit, devoted motherhood, indomitable activism and the ability to fill a room as easily with her laugh as with the music of her band, the Survivors.

Her fifth and final album in 2016 was titled Raw, an unambiguous description of her emotional state at the time. She penned the record’s confessional lyrics during her separation (and eventual divorce) from Neil Young, the iconic Canadian musician to whom she had been married 36 years.

A cathartic exercise, the songwriting with band members guitarist Kelvin Holly and the legendary keyboardist Spooner Oldham produced expressions of anger (Why), regret (Too Little Too Late) and profound hurt. If a cover version of the 1966 Nancy Sinatra hit These Boots are Made for Walkin’ conveyed sassy resiliency, an album-closing update of Don Henley’s The Heart of the Matter was a public announcement of forgiveness.

“She was at peace,” said Survivors’ bassist Shonna Tucker, who toured with Ms. Young on the band’s final run of shows in 2016 and 2017. “She was shining – we laughed, we danced, we shopped. To see her evolve and go through the phases of healing, and for her to come out the other end so strong and beautiful was truly inspiring.”

On his website, Mr. Young published a public statement following his ex-wife’s death: “Thanks Pegi, for being such a wonderful mother to our children. You live on inside of them and the many you have touched.” The message also referenced Mr. Young’s song Such a Woman, a piano-based devotion from his 1992 album Harvest Moon.

The couple married in 1978 and raised a family at Broken Arrow Ranch, a sprawling 57-hectare compound in the hills above Woodside, Calif. They had two children – first a son, Ben; then a daughter, Amber Jean. Mr. Young also had shared custody of his son Zeke, the product of an earlier relationship with actor Carrie Snodgress.

Ben lives with cerebral palsy. Finding the local school system wanting when it came to meeting the needs of a severely impaired son, Ms. Young (with Jim Forderer, a fellow parent of a child with specialized educational needs, and speech-language pathologist Dr. Marilyn Buzolich) co-founded Bridge School. “She realized that if the schools weren’t good enough for her son, they couldn’t be good for anybody else,” said Paul Morton, younger brother to Ms. Young. “So, she decided to do something about it.”

In his 2012 memoir Waging Heavy Peace, Mr. Young described his former wife’s Bridge School spearheading and the annual music festival which helped sustain the institution financially. “It was her idea,” he wrote. “She just blurted out, ‘Why don’t we just call your friends and put on a concert to raise money and start a school? We could get Bruce Springsteen.’ ”

They could, and did. In 1986, Mr. Springsteen (along with Tom Petty, Robin Williams, Mr. Henley and an unannounced Crosby, Stills, Nash and Young) headlined a fundraising show at Shoreline Amphitheater in Mountain View, Calif. The annual Bridge School Benefit, which over the years brought to stage such diverse acts as Arcade Fire, Cheech Marin, Tony Bennett, John Lee Hooker, Alanis Morissette, Elton John, Pearl Jam, Paul McCartney, Sheryl Crow and The Who, continued until 2016.

To Mr. Young, the sheer boldness of the out-of-the blue idea behind the school and the concerts by his then-wife was striking. “I just looked at her,” he would later write, “dumbfounded by this audacious idea.”

It was not the first time someone close to Ms. Young was surprised by her, and it would not be the last.

The daughter of Tom Morton and Margaret Foley, Margaret Mary Morton was born on Dec. 1, 1952. When she was growing up with her five siblings in San Mateo, Calif., her nickname Peggy was eventually stylized as Pegi. She wrote poetry, but kept the journals to herself. “She wrote down her thoughts and always had a guitar,” Paul Morton said. “She was a free-spirit, emblematic of her time.”

In 1971, the teenaged Ms. Young embraced the freewheeling era by hitchhiking across the country and into Canada, with only a large pet for companionship. “Of course she got stuck in Wawa, Ont.,” Neil Young, who did not know her at the time, once quipped to a journalist. “And the dog didn’t help.”

By 1972, Ms. Young and said dog made it back to Northern California, where she lived in a teepee she bought for $200. Two years later, while working as a hostess at Alex’s Mountain House she met her future husband, a frequent customer at the restaurant situated near his ranch.

“I loved her instantly,” Mr. Young recalled in Waging Heavy Peace,” referring to the young, blonde Californian. “In [her] eyes I saw myself and a life I hoped I would be able to hold together,” wrote the previously-married musician whose various romantic relationships had not endured.

Despite Mr. Young’s rapid infatuation, the pair’s initial friendship took years to develop into something more serious. They would marry on Aug. 2, 1978, at Mr. Young’s beach home in Malibu, Calif.

Ms. Young had kept the courtship private. “Our family’s awareness of Pegi and Neil’s emerging relationship was almost non-existent,” Ms. Young’s brother said. “It wasn’t until they married before Pegi brought him home. My mother called me and said that my sister had married Neil Diamond. I told her I didn’t think that sounded right.”

The married couple settled into Broken Arrow, which Ms. Young transformed into a family home she fell in love with.

According to his long-time friend and manager, being married to Mr. Young was no easy proposition. “Neil is a very, very difficult man,” Elliot Roberts told the musician’s biographer Jimmy McDonough in 2002. “He’s very self-absorbed. He’s a true artist. It’s a very hard balance, their life and their family – and I think Pegi has done a heroic job of handling pressure. She’s done it with great grace.

In addition to her deep involvement with the Bridge School, Ms. Young performed with the Survivors at the annual Farm Aid benefit festivals and was involved with Rainforest Connection, an international group dedicated to the prevention of illegal deforestation.

Ms. Young’s musical aspirations remained untapped for years. “She felt raising her family and being a guiding force in their lives was her job,” said Bill Bentley, a friend and former publicist for Pegi Young and the Survivors. “But she approached life as an art project. She saw herself as a musical artist, and eventually she began making the music she’d waited her whole life to share with the world.”

Beginning with her eponymous solo debut in 2007 and finishing with 2016’s Raw with the Survivors, the brassy-voiced Ms. Young released five albums of R&B-influenced rock and introspective singer-songwriter fare. With family commitments lessened, she toured regularly.

After her 2014 divorce, Ms. Young remained at Broken Arrow. She modernized the ranch’s recording studio in hopes of inviting other artists to make music on site. It was there she recorded one of her final songs: You Won’t Take My Laugh Away From Me, a scathing folk-rock articulation of betrayal and defiance.

Those who knew her remember Ms. Young as a joyful soul. “She laughed and smiled with her whole face and her whole body,” said band-member Ms. Tucker. “It was the most infectious and wonderful laugh you’ve ever heard. She was a rock star on the last tour. It was special to see her be so free and doing what she loved.”

Ms. Young leaves her two children with Mr. Young, Ben and Amber Jean; stepson, Zeke; two grandchildren; five siblings; and two step-siblings.