Msgr. John Powis, whose kinetic street ministry and civic leadership helped revive some of Brooklyn’s most troubled neighborhoods, died on Sept. 29 at a nursing home in Manhattan. He was 87.

The cause was complications of Parkinson’s disease, his sister Katherine Powis said.

He belonged to a generation of clerics committed to social justice — a cohort profoundly affected by the liberalization of church policies and practices approved by the Second Vatican Council, which was convened by Pope John XXIII in 1959, the same year that Father Powis was ordained.

As the Roman Catholic pastor of Our Lady of the Presentation Church in Brownsville in the 1960s, Father Powis was a figure in the fight to improve neighborhood schools through local control. He was elected to a newly created local school board, an experiment in decentralization, in Ocean Hill-Brownsville, a mainly Black district. When a group of mostly white teachers were transferred in 1968, the teachers’ union staged a citywide strike, which had enduring political and racial repercussions.

Father Powis was also a force in creating affordable housing. He was a founder of East Brooklyn Congregations, the politically potent coalition of religious groups behind the Nehemiah Project, which transformed acres of derelict lots into thousands of one- and two-family subsidized homes.

And from 1989 until his official retirement in 2004, he served as pastor of St. Barbara’s, a majestic century-old Mediterranean-style church with cream-colored spires that towered over Bushwick and where attendance on a typical Sunday grew from 200 worshipers to 1,400 under his leadership.

As pastor there, he was instrumental in helping the community cope as its concerns shifted from fear of arson, the despair that lingered after a rampage of looting during the 1977 blackout and other problems to worries about being displaced as new housing and improved security made the community ripe for gentrification. He also squared off against the local assemblyman, Vito Lopez, whom he accused of injecting politics and patronage into local social service programs.

The revival of St. Barbara’s, and of Bushwick, Father Powis told The New York Times in 1997, was “like a proclamation that life can triumph over death.”

John Joseph Powis was born on Nov. 10, 1933, in Brooklyn to Edward D. Powis, a bank loan officer and son of a Welsh immigrant, and Margaret (Fasano) Powis, a homemaker. He was raised in Brooklyn’s East New York and City Line sections.

In addition to his sister Katherine, he is survived by his sisters Ellen Powers, Mary Carter, Margaret Hanley and Bernadette Powis, and his brothers, Michael and David Powis.

Even as a child, his family said, he felt a calling to the priesthood, solemnly celebrating his own version of Mass on a miniature alter that relatives had given him.

After graduating from Cathedral Preparatory School in Brooklyn, he enrolled at Immaculate Conception Seminary in Huntington, N.Y. One summer, when he was considering taking more courses or possibly going South to volunteer in the civil rights movement, his spiritual adviser at the seminary, the Rev. James Coffey, steered him instead toward social work in Brooklyn.

“There are so many people from the South coming here who need help, too,” Katherine Powis quoted Father Coffey as saying. “That changed Jack’s life.”

While at the seminary, he sold beer at night during Dodger games at Ebbets Field for pocket change and volunteered during the day with nuns of the Missionary Servants of the Holy Trinity at the Fort Greene and Farragut housing projects in Brooklyn’s Fort Greene section.

“I had never had any contact with a Black or Hispanic person before,” he said in an interview with the journal City Limits in 2002.

To cope in neighborhoods where the population was becoming overwhelmingly Hispanic, after his ordination he became fluent in Spanish through frequent visits to Puerto Rico, where he was tutored by Ivan Illich, the priest turned philosopher.

“He is known by generations of Latinos who often survive only on his ability to catch people who start wandering in despair and bring them back to try again and hope with him,” Jimmy Breslin wrote in “The Church That Forgot Christ” (2004).

In 1963, he was named pastor of Our Lady, where he joined demonstrations against the city’s plans to remove fire alarm boxes on the street and appeared in Housing Court on behalf of residents to stave off evictions. He let some who were evicted stay in the rectory.

Michael Gecan, who was chief Brooklyn organizer for the Industrial Areas Foundation, a national community organizing group and a pivotal figure in the Nehemiah Project, said that Father Powis was an adherent of “something we call ‘public love’ — a deep connection with parishioners and neighbors, a commitment to them that is unbreakable, and a spirit of hope and possibility that others feel and respond to.”

People didn’t always respond that way. One morning in 1972, he was forced at gunpoint to open a safe and relinquish $1,800 in bingo money by JoAnne Chesimard and two other members of the Black Liberation Army. When he struggled with the combination, one said, “We usually just blow the heads off white men,” he told the Village Voice in 2009. “I guess I was lucky.”

He later became active in an organization of progressive priests called Voice of the Ordained.

“He was a trusted go-to shoulder to cry on for so many people,” said Fran Barrett, a state coordinator for nonprofit agencies. “And yet he found the joy and love in life, and the spirit of trying to do good in everyone,” she added. (Father Powis presided over her wedding to Wayne Barrett, the journalist and author.)

Combustible about social injustice and consoling in personal crises, Father Powis straddled his civic and ecclesiastical roles by often wearing a nonthreatening flannel shirt over his clerical garb. He viewed his parishes as a church without walls, ministering to anyone in need on the street and to those who lined up nightly waiting for him to lighten their woes, if merely by listening without being judgmental.

“We try to connect religion with real life,” Father Powis told The Times in 2000. “Religion is not an opiate. You have to be involved and make a change in the community.”