A post on Mr Cain’s Twitter account announced the death. Mr Cain, a former CEO of a major pizza chain who went on to become an ardent supporter of US President Donald Trump, had been ill with Covid-19 for several weeks.
It is not clear when or where he was infected, but Mr Cain was admitted to hospital less than two weeks after attending Mr Trump’s campaign rally in Tulsa, Oklahoma, in June.
Mr Cain had been co-chairman of Black Voices for Trump.
“We knew when he was first hospitalised with Covid-19 that this was going to be a rough fight,” read an article posted on the Twitter account.
“He had trouble breathing and was taken to the hospital by ambulance. We all prayed that the initial meds they gave him would get his breathing back to normal, but it became clear pretty quickly that he was in for a battle.”
You're never ready for the kind of news we are grappling with this morning. But we have no choice but to seek and find God's strength and comfort to deal... #HermanCain https://t.co/BtOgoLVqKz
— The Cain Gang (@THEHermanCain) July 30, 2020
Mr Cain, who had hoped to become the first black man to win the Republican nomination, was initially considered a long-shot candidate. His bid was propelled forward in September 2011 when he won a straw poll vote in Florida, instantly becoming an alternative candidate for Republican voters concerned that former Massachusetts governor Mitt Romney was not conservative enough.
But Mr Cain struggled to respond to accusations that he had sexually harassed several women and – in a video that went viral on the Internet – rambled uncomfortably when asked whether he supported or opposed then-president Barack Obama’s policies in Libya. There were also gaffes on abortion and torture that led Mr Cain’s critics to question whether he was ready for the White House.
Just as Mr Cain started surging in the polls, Politico reported that the National Restaurant Association paid settlements to two former employees who claimed Mr Cain sexually harassed them while he was CEO and president of the lobbying group from 1996 to 1999.
Another woman, Sharon Bialek, said that Mr Cain, an acquaintance, groped her in a car in July 1997 after they had had dinner in Washington. Ms Bialek, who was then unemployed, said she had contacted Mr Cain seeking job advice.
Mr Cain said he could not remember Ms Bialek and denied sexually harassing anyone.
Polls in the weeks afterwards showed Mr Cain’s popularity had slipped considerably.
Mr Cain honed his speaking skills in the corporate world, then hosted a radio talk show in Atlanta that introduced his political views and life story to many Tea Party supporters and other conservatives.
But he repeatedly fumbled under the scrutiny that follows a front-runner for the presidency. He gave a rambling response when asked by the editorial board of the Milwaukee Journal Sentinel whether he supported or opposed Mr Obama’s policies in Libya. The videotaped interview went viral on the internet.
Herman Cain embodied the American Dream and represented the very best of the American spirit.
Our hearts grieve for his loved ones, and they will remain in our prayers at this time. We will never forget his legacy of grace, patriotism, and faith.— Kayleigh McEnany 45 Archived (@PressSec45) July 30, 2020
Mr Cain’s run for the presidency was unlikely, considering his origins. Born in the segregated South, he joked that his family was so poor it was “po”.
His father worked three jobs as a caretaker, barber and chauffeur, while his mother was a servant. He graduated from Morehouse College, a historically black college for men in Atlanta, received a master’s degree from Purdue University and worked as a civilian mathematician in the US Navy.
Mr Cain is survived by his wife, Gloria Etchison, their children and grandchildren.