The flags at the Scottish Parliament were lowered to half mast on Tuesday as a mark of respect to the former Conservative MSP.
Sir Alex was a popular and respected figure at Holyrood where he served as a MSP for 17-years. Scottish Conservative leader Ruth Davidson described him as a “proper gentleman” who will be mourned by all who knew him.
First Minister Nicola Sturgeon said he was “a dedicated parliamentarian with friends and admirers from across the political spectrum”.
The Scottish Conservatives said Sir Alex died at home after a short illness, surrounded by his family.
He stood down from Holyrood in 2016 after 17 years as an MSP and was knighted for services to politics and public life in the same year.
He served as the Parliament’s third Presiding Officer from 2007 to 2011.
A hill farmer before entering politics, he was first elected for the South of Scotland region and later became MSP for the Galloway and Upper Nithsdale constituency, re-drawn in 2011 as Galloway and West Dumfries.
Ms Davidson said: “Alex Fergusson was a proper gentleman. His decency, compassion and wisdom earned him friends across all parties. His passing will be mourned by all who knew him.
“He wasn’t just a major figure in the Scottish Conservatives, he was also, as the Scottish Parliament’s third Presiding Officer, a hugely significant figure at Holyrood and a stout defender of the Parliament. He enjoyed the respect of every MSP in the chamber.”
Scottish Secretary David Mundell said: “To me, Alex was foremost a great friend and I will miss him dearly.
“He is the most thoroughly decent person I have ever known. He was the absolute opposite of the career politician and was guided by a sense of public duty and his core values of family, community and country, rather than party dogma.”
Ms Sturgeon said: “Alex was a much-loved member of the Scottish Parliament – as a politician he had the rare gift of being able to argue his own case forcefully while at the same time always remaining on warm and friendly terms with his political
Alex Salmond described him as “scrupulously fair” and a “thoroughly decent man”.
Labour’s Richard Leonard said Labour’s thoughts were with his family saying he served with “diligence and dedication.