That is probably down to him being a very well-behaved Dunedin-based list MP who has no unusual passions or strange habits.
He avoided scandals and soapboxes in his first term as an MP, and has spent all of his second term in the highly demanding and important job of Chief Government Whip.
But to parliamentary inmates, his promotion came as no surprise.
From the moment he arrived in 2008 with a large cohort of new arrivals he was earmarked for higher office.
The interface of the private and public health sector was his specialty with a background as accountant and manager.
He worked for some time at ACC and Dunedin Hospital and has a master's degree in health from the University of New South Wales.
When the new National Government launched into its contentious ACC reforms, Mr Woodhouse made a strong impression as confident, articulate and knowledgeable advocate of the policy, much more so than more experienced MPs.
In the second term he was destined to get a select committee chairmanship or a whip's role - both are considered stepping stones to ministerial appointment, but more so a whip. Plenty of select committee chairs don't make ministers. But almost all senior whips do.
Whips have to manage the back bench and ensure that the Government doesn't lose any votes.
It's a job that requires organisational skills more than popularity and Mr Woodhouse is seen as fastidious in his organisation.
He has more combativeness than the sort of bonhomie that endeared predecessors such as Don McKinnon, John Carter and Simon Power to political enemies but is still regarded as a pleasant enough fellow.
He departed from tradition and attacked Labour in his speech over what he saw as a propensity to drown business in red tape and to control people's lives.
He lamented "an ideological mindset" that prevented better use of spare capacity in private hospitals and which had been to the detriment of New Zealanders' health.
Just before entering Parliament Mr Woodhouse was chief executive officer of Mercy Hospital in Dunedin.
He was born and raised in Dunedin in a large Labour-supporting Catholic family, the fifth of nine children.
In his maiden speech he made mention of the story of the Sisters of Mercy and their founder, Irish nun Catherine McAuley, which he said "inspires and challenges me and forms the basis of my leadership ethos".
He may be one of the first Dunedin MPs to claim he has both blue (National colours) and gold running through his veins.
He spoke of his gold-mining forebears, his great-great-grandfather James Woodhouse, who emigrated from Lancashire and in 1862 discovered gold at the junction of the Teviot and Clutha rivers near Roxburgh.
"No great wealth was passed down, however, as he purchased the Bannockburn Hotel and fathered eight children."
On his mother's side, great-great-grandfather Patrick Lyng was an immigrant from Dublin and the first butcher in Lawrence around the time of the Gabriel's Gully gold rush.
Mr Woodhouse went to St Paul's High School in Dunedin, and worked in a bank before heading overseas in 1987 to play rugby: for Dunfermline in Scotland and Broughton Park in Manchester.
He had played premier rugby in Dunedin and in Western Suburbs in Wellington, when he worked for the BNZ.
He went to Otago University as an adult student and graduated at 28 with a commerce and accounting degree.
Mr Woodhouse will take up the responsibilities of Immigration, Veterans Affairs and Associate Transport, the latter traditionally beingthe minister responsible for road safety.
As Immigration Minister he will be responsible for policy and not for the painstaking work of sifting through individual cases pleading for a discretionary ministerial decision.
That will be done by Ms Kaye in her new role as Associate Immigration Minister - an unusual situation in that she will report to him despite her being in the Cabinet and therefore more senior to him.
As Veterans Affairs Minister, Mr Woodhouse will also be responsible for the major events planned for 2015 to mark the 100th anniversary of the Gallipoli landing.
Mr Woodhouse is the first Dunedin-based National Party minister.
He is married with three daughters.
