By 2012 he was famously shaking the Queen's hand in Belfast.
Mr McGuinness became deputy first minister in 2007.
He wished the monarch well in Irish, in a phrase that translates as: "Goodbye and God bless".
At the time a frail and emotional McGuinness told a large group of supporters gathered outside his home in the Bogside area of Northern Ireland's second city that it broke his heart that he had to bow out of politics.
Even after the Sinn Fein party - the IRA's legal, public face - started to run for elections in the 1980s, McGuinness insisted as Sinn Fein deputy leader that "armed struggle" remained essential.
He was second in command at the time of Bloody Sunday in 1972, when British soldiers shot 26 unarmed republican protesters in Derry, killing 13 of them.
He was convicted by the Republic of Ireland's Special Criminal Court after being arrested near a vehicle containing explosives and ammunition.
Irish Times columnist Fintan O'Toole argued in January 2017 that McGuinness had been "a mass killer - during his period of membership and leadership the IRA killed 1,781 people, including 644 civilians - whose personal amiability has been essential to the peace process".
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A statement from his Sinn Fein party said he died on Tuesday in Derry following a short illness.
McGuinness moved into politics relatively early, becoming one of five Sinn Fein members elected to the short-lived Northern Ireland assembly in 1982. An MI6 agent codenamed "The Mountain Climber" met McGuinness several times as part of wider diplomatic efforts that delivered a 1994 IRA truce and, ultimately, multi-party negotiations on Northern Ireland's future and the US -brokered Good Friday peace accord of 1998.
Democratic Unionist Party leader Arlene Foster said: "History will record differing views and opinions on the role Martin McGuinness played throughout the recent and not so recent past but history will also show that his contribution to the political and peace process was significant".
McGuinness surprised many by forming a close working relationship with Paisley, the media dubbing the pair "the Chuckle Brothers".
McGuinness had said his ill-health, which required a period of absence from his role, was not the reason he resigned but said he was quitting politics to try to recover.
That triggered local elections in which Sinn Fein made major gains against the pro-British DUP and the two parties are now deadlocked, meaning that the British government could impose direct rule of Northern Ireland from London.
"As a political colleague of many years, and having participated together in the Presidential election campaign of 2011 that brought us all over Ireland, Sabina and I have appreciated both Martin McGuinness' warmth and his unfailing courtesy".