It comes after the child and family agency has witnessed a particularly challenging year.
The former leader of the Labour Party, who previously held several Cabinet positions, was due to step down having commenced the role in January 2019.
His first term expired on December 31, 2023 and a second term lasting two years was agreed at that stage.
In a statement today Mr Rabbitte said: “It has been an immensely worthwhile experience and hugely rewarding to observe the progress made in the area of child protection and welfare. The work of Tusla is often complex, sometimes fraught and not always understood or appreciated by the public.
“Tusla alone cannot respond effectively to the range of challenges thrown up by modern society. The misuse of drugs, mental health issues and homelessness are examples of those challenges that require a wider and more coordinated response.
“It has been a privilege to work with so many dedicated and committed people and I wish the agency well.”
Mr Rabbitte recently defended the agency’s record, saying there was a “unique” tendency to point the finger at the child and family agency when a high profile case becomes public, regardless of facts.
He wrote in his foreword on Tusla’s annual report for 2024, that demand for the agency is growing – but he felt it had “never been better equipped to meet the complex challenges rushing towards it”.
“Unfortunately, there will continue to be the occasional legacy issue and even the occasional inadequate response, as well as the certainty that new and challenging cases will emerge,” he added.
Former Labour leader Pat Rabbitte
Today’s News in 90 seconds – 31st December
During Mr Rabbite’s tenure as chair a number of cases involving children rocked Ireland.
Daniel Aruebose was reported missingafter gardaí discovered in August he had not been seen for several years. The agency had previously engaged with the family of the boy, who would be aged seven this year.
The toddler was found buried in a field in north Dublin earlier this year, with his death recently upgraded to a homicide investigation.
His case a rapid review of his file and prompted a series of “wellbeing checks” carried out on thousands of Tusla cases that were closed during the pandemic, from March 1, 2020, and February 28, 2022.
Separately in October, Ukrainian teenager Vadym Davydenko died and two others were taken to hospital, following an incident at Tusla emergency accommodation in Dublin.
In December, details from a review into the case of missing schoolboy Kyran Durnin were publicised.
Kyran, who would have turned nine-years-old this year, was last seen aged six in June 2022. The child was reported missing in August 2024.
The head of the National Review Panel (NRP) Dr Helen Buckley, said “the overarching conclusion” of the review into Kyran’s case was “the serious incident which elicited it could not have been anticipated from knowledge that was available to the Tusla social work department at the time”.
However, Dr Buckley also noted “practice and policy weaknesses”. But this did not “infer a direct or causal link between them and the outcome for Kyran,” she added.
A review was recommended of Tusla-garda protocol.
During its 2024 annual report, after 10 years in operation, the agency stated the number of child protection referrals has grown two-fold to 96,666 last year. And it expects numbers to exceed 100,000 for 2025.