The Government has appointed its first ever female Garda chief, who will take control at a time of unprecedented and sweeping reforms.
Noirin O'Sullivan had been acting Garda commissioner since her predecessor Martin Callinan stood down in March during a wave of controversies to engulf the force earlier this year.
Her elevation means women now occupy many of the top justice jobs in Ireland, including justice minister, director of public prosecutions, attorney general and chief justice.
Her appointment was made after an internationally advertised recruitment drive - the first ever open competition for the top policing role.
Congratulating Ms O'Sullivan, Justice Minister Frances Fitzgerald said she believed the new Garda chief was exceptionally well placed to overhaul and modernise the force.
"The focus must now be to ensure public confidence in policing in Ireland and to support the men and women of An Garda Siochana in their day-to-day work of keeping our communities and country safe," she said.
"This means delivering on a programme of reform, modernisation and investment with respect to organisation, processes and systems.
"The aim must be to craft a police service fit to meet the realities of 21st century crime and security."
Deputy commissioner since 2011, Ms O'Sullivan has publicly declared her backing for more openness in the Garda and committed herself to working with the new Garda Authority, the Garda Ombudsman and the Garda Inspectorate to bolster public confidence in the force.
Earlier this year, she said: "I'm pushing for massive change - not all of which will be welcomed within the organisation, inevitably - and I'm pushing for continuity, too.''
The force has been at the centre of several controversies in recent years, including allegations of wrongdoing, malpractice and corruption that led to the resignations of ex-chief Mr Callinan as well as former justice minister Alan Shatter earlier this year.
Inquiries were launched into the secret recording of phone calls at Garda stations, into whistleblower allegations of malpractice, cover-ups and a penalty points scandal as well as the bugging of the Garda Ombudsman.
Just two weeks ago, a damning two-year investigation of the force by the Garda Inspectorate found it does not record a significant amount of criminal activity and wrongly classifies many offences. The report was also scathing of management.
Dubliner Ms O'Sullivan has served in various postings around Dublin and in Tipperary since 1981 before rising to assistant commissioner in 2007.
She served in the Central Detective Unit (Drugs) at Harcourt Square and the Garda National Drugs Unit.
Since 2003 following her promotion to the rank of chief superintendent she had served in Garda Headquarters in the human resources area and later in the Garda Technical Bureau.
Retired Garda officer John Wilson, a whistleblower who was central to exposing the penalty points scandal, said the appointment was a missed opportunity to bring in an outsider to change a "poisonous and hateful culture" within the force.
"On a personal basis I wish her well in her role as the new Garda commissioner, but I have called repeatedly for the appointment of an outsider," he said.
"As far as I am concerned she will be judged by her actions, but she cannot detach herself from the gross dysfunctionality highlighted in the Garda Inspectorate report two weeks ago, along with the various other damning indictments of Garda management published over the last 12 months or so.
"She has held two of the most senior positions in the Garda Siochana since 2007. An outsider should have been appointed, someone who could come in and try and change the poisonous culture that exists within the Garda Siochana."
Mr Wilson disputed the appointment process, claiming the Government did not want an outsider and that it came under pressure from Garda associations to promote from within its ranks.
Referring to ex-Garda chief Mr Callinan's depiction of whistleblowers as "disgusting" during a parliamentary watchdog hearing, Mr Wilson said Ms O'Sullivan did not condemn the remarks.
"She was sitting beside Martin Callinan when he described myself and (other whistleblower) Maurice McCabe as disgusting," he said.
"I know she has commented on that and said it was the wrong use of words, but she didn't come out and condemn it."
Independent TD Mick Wallace, an outspoken advocate of Garda reforms who helped bring whistleblower allegations into the public arena, also expressed his disappointment.
"Noirin O'Sullivan is part of the old brigade, she's part of the hierarchy," he said. "This is too bad from the Government, I haven't been as disappointed since I was elected.
"This is just more of the same, the Taoiseach doesn't want reform, Minister Fitzgerald doesn't want reform."
But senior Opposition party Fianna Fail's justice spokesman Niall Collins welcomed the promotion, saying Ms O'Sullivan had put in a "solid performance" since taking over as interim chief.
"In taking up the permanent role of commissioner, she faces the substantial challenge of delivering on the reforms needed throughout our policing structures," he said.
"The management of An Garda Siochana, led by the new commissioner, needs to ensure more supervision, transparency and oversight in the day-to-day operations of the force."
In her first statement since being appointed, Ms O'Sullivan said it was a great honour and a very proud moment for her and her family.
"As Garda Commissioner, my focus will be on ensuring we continue to work closely with communities to keep them safe by preventing crime from taking place," she said.
"But when crime does takes place, as it does in all societies, we will put the victims of crime at the centre of everything we do and ensure crimes are investigated thoroughly and professionally."
Ms O'Sullivan said the force will build on reforms and changes to strengthen the trust and confidence in the service.