Political leaders have celebrated Jesse Jackson as a “titan” of the civil rights movement after the announcement on Tuesday of his death at the age of 84.

Al Sharpton, the veteran civil rights campaigner who Jackson worked closely with after the 1968 assassination of Martin Luther King Jr, called his friend and mentor “a consequential and transformative leader who changed this nation and the world”.

In a social media post on Tuesday, Sharpton wrote: “He shaped public policy and changed laws. He kept the dream alive and taught young children from broken homes, like me, that we don’t have broken spirits.”

Senior Democrats, the party for which Jackson campaigned twice as a presidential candidate, in 1984 and 1988, were also quick to pay tribute.

“He let us know our voices mattered. He instilled in us that we were somebody. And he widened the path for generations to follow in his footsteps and lead,” Kamala Harris, the first Black US vice-president, write in a post on X, also calling Jackson “one of America’s greatest patriots”.

Recalling her days as a young law student in Oakland, California, Harris recalled having a “Jesse Jackson for President” sticker on her car.

“As I would drive across the Bay Bridge, you would not believe how people from every walk of life would give me a thumbs up or honk of support,” she said.

“They were small interactions, but they exemplified Reverend Jackson’s life work – lifting up the dignity of working people, building community and coalitions, and strengthening our democracy and nation.”

Jackson, she said, was “a selfless leader, mentor, and friend to me and so many others”.

Other Democrats celebrated Jackson’s stature in the civil rights movement.

“America has lost a titan in the struggle for civil rights and racial justice. From his days at the side of Dr King, to his moral leadership in this century, Rev Jesse Jackson Sr spent his life pushing our nation closer to its own ideal,” Pete Buttigieg, transportation secretary during the Biden administration, said.

The Democratic Georgia senator Raphael Warnock said America had lost “one of its great moral voices”.

In a social media post he wrote: “With an eloquence and rhythmic rhetoric all his own, Jesse Jackson reminded America that equal justice is not inevitable; it requires vigilance and commitment, and for freedom fighters, sacrifice.

“His ministry was poetry and spiritual power in the public square. He advanced King’s dream and bent the arc of history closer to justice.”

Stacey Abrams, another prominent Black Georgia Democrat and a voting rights advocate, said Jackson “understood the immense promise of America and his role in shaping its destiny”.

“With courage, tenacity and an audacious spirit, he widened our capacity for imagining true unity and deepened our commitment to justice for all. I was one of the lucky beneficiaries of a vision he never forsook. God bless him and the Jackson family,” she wrote.

Bernice King, daughter of Martin Luther King Jr, gave thanks for a life she said “pushed hope into weary places”.

In a post on X, King wrote: “Rev Jesse Jackson Sr devoted his life to lifting people in poverty, the marginalized, and those pushed to society’s edges. He pushed barriers and opened doors so Black people and other excluded communities could step into opportunity and dignity.

“With the Rainbow Coalition, he cast a bold vision of an inclusive society – uniting people across race, class, and faith to build power together and expand the table of economic opportunity. He was a gifted negotiator and a courageous bridge‑builder, serving humanity by bringing calm into tense rooms and creating pathways where none existed.”

King said her family shared “a long and meaningful history with him, rooted in a shared commitment to justice and love”.

Donald Trump, in a post on his own Truth Social network, called Jackson “a good man”, and a “friend” who he claimed to have provided office space in New York for his Rainbow Push Coalition.

Trump’s post, as is often the case, quickly turned political, and about himself. The president attacked the “scoundrels and Lunatics on the Radical Left” who, he said, “falsely and consistently” called him a racist, and sought recognition for “funding Historically Black Colleges and Universities (HBCUs), which Jesse loved”.

Trump also took a swing at a familiar political foe, former president Barack Obama, whom, he claimed, Jackson “could not stand”.