Rev. Jesse Louis Jackson Sr., whose impassioned plea to “Keep hope alive!” buoyed Black America through transformative political, social and economic campaigns over a seven-decade career in public life, died Tuesday at age 84 after a long struggle with a neuro-degenerative disease.

From his early work with Rev. Martin Luther King Jr. and the Southern Christian Leadership Conference (SCLC) through his leadership of Chicago-based Operation People United to Save Humanity (PUSH), his candidacy in two presidential contests and his later role as a senior figure in the fight for African American empowerment, Jackson was an electrifying civil rights icon who attracted both praise and controversy.

A family statement released from his home in Chicago praised his lifelong work on behalf of those living on the margins of society. “His unwavering commitment to justice, equality and human rights helped shape a global movement for freedom and dignity,” they said. “A tireless change agent, he elevated the voices of the voiceless — from his presidential campaigns in the 1980s to mobilizing millions to register to vote — leaving an indelible mark on history.”

Jackson’s globe-trotting travels to every corner of the planet often brought him to Boston, where Mel King’s “Rainbow Coalition” campaign for mayor was adopted as Jackson’s own theme for his 1984 run for the White House. A Concord Baptist Church rally Jackson headlined in 1983 was one of the highlights of King’s historic candidacy, which propelled the South End state representative to become the first Black finalist in a Boston mayoral contest.

Tall, handsome and charismatic, the athletic ex-college quarterback drew on the cadences of the Black church and swaggering street smarts to bring audiences to their feet and cheer his appeal for a more just social order and shared humanity. Unabashedly Black and proud, he preached moral uplift with such sound bite aphorisms as “It doesn’t take a man to make a baby. It takes a man to raise a baby!” and “Up with hope, down with dope!”

A year after stumping for King, Jackson’s multihued coalition of white, Black, Latino, and LGBTQ support echoed the Boston model in supercharging minority voter registration and winning millions of ballots in a year when Republican Ronald Reagan swept to an overwhelming presidential reelection victory over eventual Democratic nominee Walter Mondale.

The broad reach of Jackson’s coalition was evident in a rollicking March 1984 campaign event at Dorchester’s Strand Theatre. Jackson arrived at the Uphams Corner theater after coming from a tense meeting with Jewish leaders in Framingham in the wake of calling New York City “Hymietown” in a muchcriticized conversation with Black reporters he thought was off the record. The Boston audience, left waiting for hours as the candidate ran overtime, erupted in cheers as Jackson entered the hall and joyfully shouted “I am somebody!” in response to his calls of affirmation and identity from the podium.

“The most important thing is that Jesse decided to do it and ran,” said former state representative Byron Rushing of the 1984 campaign. “To Black folks, once he was in that was all that mattered. And he learned a lot from that campaign. He was very important for any Black person who ran for office after Jesse had. I don’t know if Barack Obama would have won without Jesse coming before him.”

Jackson got a prime speaking position at the Democratic National Convention in San Francisco in 1984 and used it to reiterate the message that animated his career — standing up for the poor in moral appeals drawing from the Bible and his own life history. “My constituency is the desperate, the damned, the disinherited and the despised,” he said. “They are restless and seek relief.”

A few years later, at a small meeting with schoolchildren at the Museum of African American History on Beacon Hill, Jackson sat in a chair and quietly shared his life story of rising from poverty in South Carolina — the son of an unwed teenage mother — and, inspired by King — leading civil rights protests and fighting for the keystone issues of better housing, health care, educational opportunities and employment. “There is nothing you can’t do,” said Jackson to the wide-eyed youngsters. “Believe in yourself and others will believe in you.”

Running again for president in 1988, Jackson garnered millions of votes in a Democratic primary campaign eventually won by Massachusetts Gov. Michael Dukakis. Louis Elisa II, then working in the governor’s environmental affairs office, enlisted in the Jackson camp and found strong support not only in Black neighborhoods but also in white progressive enclaves in the South End and Cambridge.

Prominent Black Dukakis advisers like the late Joe Warren were infuriated with Elisa, he said. “But I wasn’t just committed because he was running,” said Elisa. “I wanted to see change. Working for him was always an amazing political adventure. I’ve been in many campaigns, but he was the candidate the most committed to grassroots organizing and putting boots on the ground.”

Elisa remembered being deeply moved by seeing white farmers from Iowa and Missouri crying in the aisles during Jackson’s stirring address to delegates at the Democratic National Convention in Atlanta. Jackson, who had won seven million primary votes, spoke directly to those who felt abandoned. “Call you outcast, low down, you can’t make it, you’re nothing, you’re from nobody, subclass, underclass,” he said, “when you see Jesse Jackson, when my name goes in nomination, I was born in the slum, but the slum was not born in me. And it wasn’t born in you, and you can make it.”

Born in the Jim Crow south, Jackson was mostly raised by his grandmother and showed early promise in the Greenville, South Carolina, public schools. A brief stint at the University of Illinois Urbana-Champagne on a football scholarship left him disillusioned when he was told Blacks couldn’t play quarterback. A transfer to North Carolina A&T led to a leadership role in student protests in Greensboro and a meeting with his future wife, Jacqueline “Jackie” Lavinia Brown.

Jackson’s studies at the Chicago Theological Seminary ended after he went South to meet King and became head of the SCLC’s Operation Breadbasket in Chicago, an economic empowerment strategy that used boycotts to increase Black hiring and contract opportunities.

In April 1968, Jackson was in Memphis with King to march with striking sanitation workers and was standing near the Nobel Peace Prize laureate on the second-floor balcony of the Lorraine Motel when a single shot ended his life. Jackson rankled older King associates for wearing the blood-stained turtleneck he had on during the shooting while being interviewed the day after.

Jackson, ambitious and magnetic, clearly sought to inherit the King mantle in the wake of the assassination and proved adept in the ensuing years to command attention for himself and the movements he headed. Operation PUSH, which he founded after leaving the SCLC, used aggressive tactics to change vendor and hiring policies at major corporations. Jackson traveled the world, making alliances with Palestinian leaders and African presidents. He campaigned relentlessly for President Jimmy Carter in his unsuccessful reelection bid in 1980 before taking his own plunge into electoral politics four years later.

After his presidential campaigns, Jackson’s rechristened Rainbow PUSH Coalition continued to pressure corporate America to embrace Black economic empowerment, but he left runs for electoral power to others, most notably Obama. Photographs from Obama’s Grant Park election night victory rally in 2008 showed Jackson in tears.

In 2017, Jackson announced that he had Parkinson’s Disease, and his public appearances diminished while he continued to speak out against attacks on voting rights and diversity, equity and inclusion.

Joyce Ferriabough, the well-known Boston political and media consultant who served as Jackson’s 1984 press secretary, said she always felt “his commitment to continued progress for our people. He made sure our children knew they were somebody. He was one of a kind and will always be remembered and revered for his contributions to civil rights and his love for his people.”

Jackson leaves his wife and their children, Santita, Jesse Jr., Jonathan, Yusef and Jacqueline; daughter Ashley Jackson; and grandchildren.

“Our father was a servant leader,” said the Jackson family after his death, “not only to our family, but to the oppressed, the voiceless and the overlooked around the world. We shared him with the world, and in return, the world became part of our extended family.”