Garda Commissioner Martin Callinan is to remain at the top of the force for two years more than expected.
The top-ranking officer was due to retire next August but Justice Minister Alan Shatter ordered his tenure to be extended, allowing him to continue overseeing changes and reforms.
A ban on gardai serving beyond the age of 60 years will have to tweaked to allow the police chief to continue at the helm until August 2015, according to the Department of Justice.
Mr Shatter revealed the extension after his proposals were rubber-stamped by the Cabinet.
"At a time of such significant organisational reform, I believe that it is desirable that there should be continuity in Garda leadership, and I am delighted that Martin has agreed to this extension," he said.
"His leadership over this period, during which there will be further challenges to be met, will be invaluable."
Mr Shatter said the commissioner has already presided over radical and extensive change within the force, while official figures have shown reductions in most areas of crime.
Mr Callinan was appointed the country's most senior garda in December 2010.
A father-of-three, he was formerly a deputy Garda commissioner, after serving in a wide range of roles since he joined the force in 1973, including at stations in Waterford, Blanchardstown, Cabra, Terenure and Swinford.