As a politician he mixed compassion and personal charm with an unfortunate appetite for self-destruction.
First elected in 1989, he was put on a fast track to the pinnacle of Fianna Fáil. But his speedy appointment to Cabinet was taken from under his nose. On the day of his appointment as Minister for Defence revelations broke about his sympathies with a member of the IRA. It took him six years to get another opportunity.
His subsequent five-year term as Minister for Sport and Tourism in Bertie Ahern’s first government was the high point of his career. Still, his many political choices were overshadowed by his personal demons.
A father of five, Dr McDaid has had battles with alcohol. In 2002, his estranged wife, Marguerite, wrote a book about their marriage and the destructive role his drinking played in it.
The Galway-educated GP, and acclaimed multi-code footballer, admitted his “selfish” relationship with drink meant he missed much of his children’s upbringing.
In 2006, Dr McDaid, after announcing he was retiring from politics, told an interviewer he was an alcoholic. He explained he was a binge drinker and was able to stay off booze for periods of time.
Following a brief relationship with RTÉ newsreader Anne Doyle, he met his new partner Siobhán O’Donnell. They had a son, Neal, and the desire to spend time with him temporarily convinced him to leave politics and concentrate on his practice.
Before the 2007 General Election he had a change of heart and ran again for Fianna Fáil.
Yesterday, Taoiseach Brian Cowen described the departing TD as a long-time friend. In 1991, he defended Dr McDaid the day the Donegal deputy’s appointment as Minister for Defence was torpedoed.
On that fateful afternoon Fine Gael produced a photograph of him shoulder-to-shoulder and celebrating with James Pius Clarke, an IRA convict who had escaped from the Maze prison and was twice convicted in the Republic.
In later years Dr McDaid felt more shunned by the party.
Dr McDaid fought, but lost, the battle for supremacy in the quagmire of Fianna Fáil’s Donegal north east constituency. The long-time outcast Niall Blaney won out. When the party headquarters placed Mr Blaney on the general election ticket with Dr McDaid and Cecilia Keaveney in 2007, the former minister felt the tactics were a bid to oust him.
“Fianna Fáil gave me no support whatever. I was treated as an independent deputy and everyone knows that,” Dr McDaid said in an interview at the time.
In this Dáil term the hostilities grew. Immediately Dr McDaid put taoiseach Bertie Ahern on notice that his support was not guaranteed.
He was a frequent and vocal rebel from within the parliamentary party. But he was not destined to stay there.
Taoiseach Brian Cowen’s early-morning entertainment at the most recent parliamentary party in Galway was preceded by a similar, but more low-key, controversy in 2004.
Back then, the highly publicised parliamentary party think-in took place at Inchydoney. Dr McDaid admitted it was a knees-up that went on for two days.
Shortly afterwards he was demoted from his role as Minister of State at the Department of Transport. He considered the perceptions of his, and others, socialising, forced Mr Ahern’s hand. But the fallout from his drinking was to get even worse.
In 2005 he was convicted of drink driving. At a race meeting at Punchestown he spent five hours drinking wine before getting into his car and driving the wrong way up the Naas Road dual carriageway.
Afterwards, he was unusually contrite for a man who never shirked confrontation with the public.
In 2002 he ran into difficulty for paraphrasing a grieving mother and calling those who died by suicide “selfish bastards”.
This year, he cut a lonely figure when he refused to give up his ministerial pension. He took the flak from his home in Donegal. He was always comfortable in his constituency. In 2008, he missed four out of five Dáil votes, by far the worst of any of his peers. This absence did not stop him preaching to the Government about how it should do its business.
In 2008 he was kicked out of the parliamentary party for abstaining from a vote, triggered by Fine Gael, on the failure to produce the cervical cancer screening programme.
He continued to use health issues as a lightening rod and in recent weeks threatened the Government he would against it if it cut funding for his Letterkenny General Hospital.
However, before he got the chance to vote against his political family he decided instead to walk. The TD said his resignation was purely for personal reasons, but it came with a strong statement of political misgivings.