During his 37 years in the NSW Police force he's worked in five of the eight police districts - Wollongong, Lake Illawarra, South Coast, Monaro and Hume - he now commands, which also includes Riverina, Murray River and Murrumbidgee PDs.

For 10 of those years he was in the homicide squad and worked on some of Wollongong's most grisly murders, including the 1998 murder of former Lord Mayor Frank Arkell and David O'Hearn.

He also investigated and helped see Ljube Velevski jailed for slashing the throats of his wife and three children in their Berkeley home in 1994.

He's served as Deputy Commissioner and has just wound up a two-year stint as Commander of the Professional Standards Command.

"I've worked in so many different careers like drug squad, child abuse, surveillance, operational detective, alcohol licence enforcement command, child abuse section," he said.

The 56-year-old is keen to put all of that experience to use not only in his home town of Wollongong, but south to the Victorian border where his command extends.

Key basic principles of crime, community and people (police officers) will be a focus under his leadership. He's also keen to enhance the region's policing capabilities.

He's keen to protect victims of domestic violence and bring perpetrators to court.

Drug-related crime, serious crime and emergency management - bushfires, floods, storms - are also focus areas.

"It's more about making my police, my commanders and the police who work under that command match fit and ready to step up and deliver a professional response to protect our community," he said.

"That's always a challenge and a daily focus."

It's a lot less these days than when he was first stationed at Goulburn as a 20-year-old probationary constable.

But as he's risen through the ranks, police officers who are injured or die on the job do weigh heavily on his mind.

Assistant Commissioner Cassar admits he deals with the stresses of the job better now than he once did.

"You can't control everything, but you do your best and try to get people to do their best," he said.

"At the end of the day, things are going to happen and things are going to be out of your control."

Exercise, family, mates and 5am walks with his dog all help keep things in perspective.

"I'll still either take the dog for a walk or go for a bike ride, a run and start thinking about what the day's going to look like. That's if I haven't been woken up by the tactical operations unit or by one of the commanders - you sleep less, you think more," he said.

He's lost count of how many homicides he's worked on and admits they've changed him to the core.

"I think about my children, the innocence there, and I never want them to be exposed to what I got exposed to," he said.

"But, there is obviously that midway point where you want to make them relatively street smart, without being exposed to the darker side of life."

The public have obligations when it comes to road trauma.

"It's really important that the community appreciate the responsibility and accountability that they have," he said.

"Driving safely, looking out for other road users, not taking risks, not using their phones, not speeding."

"You'll see me," he said simply.

He's not a sit-behind-the-desk kind of cop and he knows his presence is vital.

"You'll see me out in the regional areas, at the police stations," he said.

Despite the horrors of what he sees on the job, his eyes light up when asked why he sticks with a career that, at times, is very tough and dangerous.

"It is the best career path anyone could ever choose," he said.

"Every time I've moved into a new section, it's like starting a new job. To this day I'll never regret being in the police.