Face of Nation : Simon Byrne, 56, is taking over from Sir George Hamilton, who has retired after five years as Northern Ireland’s top police officer.
Two decades into the peace process, the job is still one of the most demanding in UK policing.
Mr Byrne, the third English officer to lead the PSNI, faces a range of issues the minute he walks through the door of its Belfast headquarters.
Here are five of the most pressing.
About 60 detectives are looking into approximately 1,200 deaths linked to the Troubles.
Internally, these investigations are seen as a drain on resources and the PSNI supports handing the cases over to a new, independent Historical Investigations Unit (HIU) as suggested under the 2014 Stormont House Agreement.
The delay in advancing things frustrated Sir George. Mr Byrne, provided he does not think differently, will want to see action.
The PSNI’s handling of legacy issues has contributed to growing nationalist discontent with policing, leading to problems in attracting Catholic recruits.
Some 32% of officers are Catholic, which is not representative of Northern Ireland society. There is a risk that figure may soon dip.
With the PSNI set to recruit about 500 officers this year, can Mr Byrne improve outreach quickly?
MI5 has had the lead role in counter-terrorism in Northern Ireland for 12 years, but works in close partnership with the PSNI.
Mr Byrne arrives with the New IRA, a dissident republican group, still posing a significant threat.
Last month, it planted a bomb under the car of an off-duty officer, demonstrating that despite the public backlash it faced after murdering Lyra McKee, it is still intent on using violence.
Ms McKee was shot dead while observing rioting in Londonderry’s Creggan estate in April.
A bit like legacy, Brexit is a huge issue, but it is in the political sphere and outside the PSNI’s control.
Sir George said he spent part of every day since the EU referendum looking at contingency planning. It will be no different with Mr Byrne at the helm, with a 31 October deadline looming and the continuing chance of a hard border as and when the UK leaves the EU.
A no-deal Brexit could bring unique policing challenges, as any border infrastructure would potentially have to be protected from dissident republican attack.
It is almost 20 years since policing in Northern Ireland was reformed and the PSNI came into being after a review by former Conservative Party politician Chris Patten.
A stock-take is needed and a new modernisation agenda set; the police estate, IT systems, even its vehicle fleet might all be looked at.
But with £150m having been sliced off the PSNI’s near £1bn budget in recent years, Mr Byrne may have to oversee changes, with finances as tight as ever.
