Maaka McKinney has already served his country on battlefields in Bosnia - as well as working as a security contractor protecting troops and diplomats in war-torn Iraq.
Now the Auckland firefighter - who recently left the New Zealand Defence Force - is about to begin his most personal mission: cycling the South Island and then running from Wellington to Auckland in his firefighting gear to raise funds for Leukaemia & Blood Cancer NZ and to create awareness of post traumatic stress disorder in first responders.
McKinney will begin the challenge after the Anzac Day dawn service at Auckland War Memorial Museum - cycling from Bluff to Wellington, then running to Auckland for the Fire Fighter Sky City challenge on May 13.
He will be doing it "tough" during the massive challenge, wearing full firefighter's gear - which will top 20kg - and running in his work-issue boots.
"I hope to cover 1800km in 17 days," he said.
"When I get tired I'll jump over the fence and sleep in a paddock. I'll source food on the way and I'll jump into a creek to refill my water bottles and have a wash.
"It's another day on the job. As a soldier we do battle fitness tests, walk long distances with packs on our back and weapons on our arms."
He is no stranger to charity fundraising campaigns, including supporting the New Zealand Firefighter's Charitable Trust.
Three years ago, McKinney and other volunteer firemen walked from Waitangi to the Sky Tower.
And raising awareness for post traumatic stress disorder among first responders was also something he was passionate about.
McKinney was in his teens when he joined the army. In 2002 he was deployed to Bosnia as a troop sergeant attached to the British army. Their job was to help rebuild Bosnia after the war and elicit intelligence from the locals.
Two years later McKinney was ready for another challenge - heading to Iraq as a security contractor.
"It's high danger, high threat and highly paid," he said. "You are in a war zone and on high alert."
McKinney's job was to transport US diplomats, US military, police trainers and corrections trainers around Baghdad.
His role saw him and his colleagues under constant threat of machine gun attack and booby traps with explosives that could "rip a vehicle to shreds".
McKinney is still upset when he hears stories from others who saw children being used as human bombs.
"The insurgents will give a child a chilly bin full of Coke and pay them $US10 to offer Coke to the American soldiers," he said. "The kid will take it over. They are none the wiser, then BOOM [it detonates the chilly bin]. The kid goes up and so do the soldiers, unfortunately."
But after four years living on little more than adrenalin McKinney called it quits.
He was depressed for about a year and then started drinking, sometimes on his own, to erase the trauma he had experienced.
"All of a sudden, it hit me. I found it hard sleeping, I'd wake up sweating and staring at the ceiling for hours."
Even now, when he's sitting in Auckland's traffic the sound of a car horn can trigger horror flashbacks for him.
"They were always going off in Baghdad along with the sounds of gunfire and car bombs."
McKinney said he relates to the trauma all firefighters, ambulance officers and police face.
"As a young soldier I didn't see as many fatalities as [emergency frontline staff]," he said.
"They have to extract people out of cars and pick body parts off the road - and they're not getting paid [much] for it."
He encourages all first responders to talk to each other and to not be afraid to ask for help.
"There are support measures, there is help. You are not alone and don't think you are alone."
• To follow Maaka McKinney's progress or to donate, visit: facebook.com/A-Firefighters-Run-779444255542591/