This emerged at his requiem Mass when his son, Joe Jnr, revealed that the former TD trimmed the years off following the advice of his family at a “kitchen cabinet meeting”.
The family feared that he would lose votes if the electorate found out he was over the 70 mark.
He was 76 when he died in Cork University Hospital last Monday, and not 71 as reported.
A host of big political names turned up at the Mass in Mallow to pay their last respects.
They included Labour’s new leader Eamon Gilmore, and serving TDs Michael D Higgins, Joan Burton, Emmet Stagg, Kathleen Lynch, Ciarán Lynch and Joanna Tuffy.
Circuit Court judge Pat McCartan, a former Workers’ Party TD, also attended, along with one-time Democratic Left leader Proinsias de Rossa and former Labour TDs Eric Byrne and Sean Ryan.
Chief celebrant Fr Micheál O’Lonsaigh said that no matter what political persuasion a constituent was, he or she always got a full hearing from Mr Sherlock.
“His belief was in the value of community.
“He was well able to fight his corner, and his adversaries all knew that it came from a deeply held conviction. The people of Mallow and the surrounding area are mourning his loss, but there is a greater loss being felt by his family,” Fr O’Lonsaigh said.
After Mr Sherlock Jnr revealed his father’s true age, it was the turn of sibling Seán to pay tribute to his father’s legacy.
He said the Sherlock family were taken aback by the outpouring of grief among local people, and very grateful for the genuine support they had received.
“He was truly a man of the people and often said that if you stuck by the people they’d stick by you,” he said.
He won a seat for Labour at the last general election after his father announced his decision to retire from politics.
He described his father, a former Sinn Féin the Workers’ Party TD, as “a republican in the Wolfe Tone sense”.
Shortly before the end of his speech, he broke down, but rallied and finished to applause from the 1,000-plus people who packed the Church of the Resurrection.
Mr Sherlock’s coffin, draped in the tricolour, was taken to the awaiting hearse and driven past his house before it went to St Gobnait’s cemetery.
Mr Gilmore delivered a graveside oration, saying: “I was lucky enough to have known Joe Sherlock for almost 30 years. His campaign to retain and strengthen Mallow hospital was a shining example of his dedication and commitment, and an illustration of what can be achieved when public representatives and people stand together.”