Mr Galbraith, a founding member of the Scottish Parliament, was believed to have been the world’s longest-surviving lung transplant patient.
The 68-year-old former neurosurgeon, who went on to become a Labour MSP for Strathkelvin and Bearsden, died yesterday in hospital in Glasgow from an infection.
He had received a pioneering transplant in 1990 at the Freeman Hospital in Newcastle after initially being given just a few years to live, due to a condition that hardens the lungs.
Mr Galbraith went on to enjoy years of improved health and was later to serve as minister in the first two years of devolution under Donald Dewar then Henry McLeish.
The father of three was education minister at the time of the exams crisis in 2000 when thousands of students received incomplete or inaccurate results certificates from the Scottish Qualifications Authority.
Later that year he was moved in a Cabinet reshuffle, becoming environment minister. Mr Galbraith resigned from politics in 2001 for health reasons.
He was first elected as an MP at the 1987 General Election, when he entered the Commons along with Labour figures such as former chancellor Alistair Darling, former Home Secretary John Reid and the ex-Scottish Labour leader Mr McLeish.
Mr Darling yesterday said he had been asked to put out a statement on behalf of Mr Galbraith’s family, which said: “Sam was a brilliant neurosurgeon, a dedicated politician and a very dear friend. But above all, he was devoted to his family, to Nicola and their three daughters – Mhairi, Heather and Fiona – who are foremost in our thoughts. They have asked for their privacy to be respected at this time.”
The statement continued: “Sam was believed to be the world’s longest-surviving lung transplant patient.
“It was extraordinary how he continued to contribute and achieve so much throughout the 25 years that he lived with his condition.
“Sam’s professional life and immense talents were devoted to the care and betterment of others, through the National Health Service and in his deep political commitment. He was a great humanitarian. His work and his life touched countless lives.”
Scottish Labour leader Johann Lamont also paid tribute to Mr Galbraith, saying: “Sam was a wonderful man. A great doctor, an inspiring colleague and dedicated family man.
“Sam was a great champion of the NHS, and he himself was a great example of how it can transform lives.
“We will all miss his vigour, his support and his candour. Our thoughts are with his wife and family.”
There were also tributes from Mr Galbraith’s opponents including First Minister Alex Salmond and Scottish Conservative leader Ruth Davidson, who his contribution to public life.
Mr Salmond said: “Sam Galbraith was a devoted and gifted politician whose commitment to improving the lives of others never wavered, even though he faced living with his own serious health condition for the best part of 25 years. My thoughts go to his family and friends at this sad and difficult time.”
Ms Davidson said: “Sam Galbraith was a good public servant and an honest, decent man. Scotland is very much the poorer for his passing.”
Holyrood’s Presiding Officer, Tricia Marwick, said: “Sam was no career politician – a distinguished neurosurgeon with a hinterland beyond politics. He was one of the original 1999 intake of MSPs, but there was always a sense that parliament was robbed of his talents when he stood down in 2001.”