On his return to Christchurch, the 55-year-old will star as Toad in a stage version of The Wind in the Willows before filming a new World War One film in Canada.
He'll then call on his background in events management to help organise the navy's 75th anniversary celebrations in 2016.
"At the moment I'm just doing enough hours to keep momentum moving on the 75th. But as we get nearer to 2016 it'll be a fulltime job, and acting may have to take a back seat for a while."
Although his acting career has soared in recent years, the sea has been in Hadlow's blood.
Born in Australia, his father was a naval chaplain whose work took the family to India for three years.
Hadlow arrived in New Zealand aged 9, growing up in Wellington and Christchurch.
After leaving boarding school, he joined the navy and spent three years playing trumpet in the band.
He turned his attention to acting, picking up his first on-screen role in 1979 kids series, Children of Fire Mountain.
After several small film roles, Hadlow voiced a number of characters in Sir Peter Jackson's 1989 puppet movie Meet the Feebles.
Since then, he's starred in short films, The Billy T James Show, TV adverts, presented What Now? and acted and directed at Christchurch's Court Theatre.
He also worked as events manager at Christchurch City Council before leaving to star in The Hobbit.
Hadlow joined the navy reserves five years ago, and has since been made a lieutenant.
"I'm very honoured and privileged to have a commission," he said.
"It's a great organisation to belong to, actually. The fitness side is very important - I have to pass a fitness test every six months.
"I don't get out on the water very much, but I'm chasing some courses so I can get some experience on ships. It's the perfect job to have while I'm acting."
While he's keen to ensure the navy celebrations are "out of this world", Hadlow is ensuring he enjoys the success and stardom that go with a lead role in The Hobbit.
"As an actor to have a gig for two years, on a major film, is quite an endorsement," Hadlow said.
He's looking forward to the premiere, which he thinks will be the start of a whirlwind ride.
"It's extraordinary to be a part of. Filming was so much fun and now it's just going to go nuts. The Lord of the Rings went ballistic, but I think this is going to go into another stratosphere. It's wonderful."