Karen Webb will become the first female NSW police commissioner, replacing Mick Fuller who is retiring next year.
Premier Dominic Perrottet announced Deputy Commissioner Webb will take on the role in April.
"This is an important role, not just in leading the 17,000 members of the NSW Police Force, but importantly ensuring the safety of the eight million people across our state," he said on Wednesday.
"So, this is a very important decision ... there are probably no more important appointments that we can make.
"I believe Deputy Commissioner Webb has the honesty, the integrity and the drive to lead the NSW Police Force at this challenging time."
In April Mr Fuller will end his three decade career in the NSW Police Force, and a five-year stint as commissioner after taking over from Andrew Scipione in 2017.
Ms Webb also has a storied career with the police force in NSW, joining the Castle Hill Police Station in 1987.
She worked as a detective before rising to the rank of commander in 2003.
Ms Webb went on to serve as the assistant commissioner in charge of the Public Safety Command, then the Traffic and Highway Patrol, before she was promoted to deputy commissioner five months ago.
Ms Webb edged out popular candidates including Deputy Commissioner Mick Willing, a former Homicide Squad Commander who led the state's bushfire recovery response.
Deputy Commissioner Mal Lanyon was also among the favourites for the role.
Mr Perrottet thanked them both.
"It is an absolute credit to the NSW Police Force that we were blessed with such strong candidates with very high calibre who have served our state with absolute distinction," he said.
Australian Associated Press