Australia got its first Catholic saint Sunday, a feisty 19th-century nun who was briefly excommunicated when her colleagues exposed an abusive priest.

Mary MacKillop co-founded the Sisters of St. Joseph of the Sacred Heart in 1867, and gained a reputation as the first Australian nun to leave the cities and minister to the rural poor.

Nuns in her order got evidence that a priest was engaged in “scandalous behavior,” said the Rev. Paul Gardiner, who has spent decades researching MacKillop’s life.

The nuns reported it to the Rev. Julian Woods, MacKillop’s first spiritual mentor who co-founded the Sisters of St. Joseph.

Woods in turn reported the abuse to church authorities, resulting in the Rev. Ambrose Patrick Keating being sent back to Ireland from Kapunda, Australia.

But Keating’s friends “were really upset with Father Woods and thought they could best get at him by getting at Mary,” said Claire Larkin, the chair of the Mary MacKillop Centre in Penola, Australia.

“They told a lot of lies to the bishop,” who excommunicated MacKillop and the entire order in 1871, she said.

Bishop James Quinn revoked the excommunication five months later, on his deathbed, the order says in its biography of Mary MacKillop.

But she still had to spend decades fighting local Catholic leaders for control of the order she founded.

“She was a charismatic entrepreneur,” the Rev. Thomas Reese, author of “Inside the Vatican,” told CNN. “She was a feminist before her time. She struggled in a male-dominated institution and got things done.”

Her familiarity with church politics may have played a role in the instructions she issued to her nuns when women got the vote in Australia.

“It is the duty on us all to vote … Get advice from some leading man in whom you have confidence or from the priest, but keep your voting secret,” she wrote in 1903.

The order grew to include 300 nuns in Australia and New Zealand by 1891, its website says, and now has about 1,200 members.

She died in 1909 and was beatified by Pope John Paul II in 1995.

The Catholic Church credits her with miraculously helping to cure a woman named Kathleen Evans of cancer.

She took to wearing a piece of MacKillop’s clothing pinned to her nightgown and asked her family and friends to pray for MacKillop to intervene with God on her behalf.

Her cancer disappeared, Evans said in a statement.

Pope Benedict XVI recognized the cure as a miracle in December 2009, and announced two months later that MacKillop would be canonized.

He praised her “courageous and saintly example of zeal, perseverance and prayer” on Sunday in canonizing her as St. Mary of the Cross MacKillop.

Some 4,000 people attended an outdoor mass Sunday to celebrate the canonization in Penola, where she started her ministry in a disused stable.

“It’s so exciting, we’ve had a marvellous day,” Larkin said.

“It’s been a long journey” to sainthood, she said. “Her dream started in a little country outback town, to think that she’s gotten that recognition.”