The 51-year-old second-term MP has been appointed attorney-general and Treaty negotiations minister in Prime Minister elect John Key's new-look Cabinet .
A lawyer by trade, Mr Finlayson said dubbing him a gay MP was one-dimensional.
"There are many parts to my being. I think it's a bit foolish to self-define people. It's just as stupid as describing me as a Catholic MP," he told NZPA in a 2005 interview.
Growing up in the well-to-do Wellington suburb of Khandallah, Mr Finlayson studied Latin, French and Law at Victoria University and was admitted to the bar in 1981.
He was a partner in Brandon Brookfield from 1986 to 1990, before joining major law firm Bell Gully, where he was a partner until 2003.
He then became a barrister specialising in public law and judicial review up until his election on National's list in 2005.
He was involved in many Treaty of Waitangi cases and acted for Ngai Tahu for many years.
He said he was "quite enthusiastic" about Treaty matters.
National has promised to settle all historic Treaty claims by 2014, a target Mr Finlayson believes is achievable.
"I want to get stuck in to try and help resolve them because I know how good it is for iwi when they are resolved and people let go of the past and look forward to the future."
Joining National in 1974, Mr Finlayson worked his way up the party ranks. He was its North Island chairman from 2001 to 2003 and after the last election was chairman of National's policy committee.
He said he was attracted by the party's personalities and philosophy.
"I consider myself not a conservative at all. I consider myself a liberal, a liberal conservative."
In his maiden speech to Parliament Mr Finlayson outlined a personal quest to improve the quality of what he saw as frequent poorly worded and vague legislation .
Vague references to Treaty principles were an example of poor law making.
"On numerous occasions I have made submissions to judges trying to interpret references to Treaty principles in a particular concept," he said.
"This is because politicians did not give proper consideration to the implications of the language they used in legislation."
The list MP said more care needed to be taken to ensure that legislation was carefully drafted and reflected the intention of Parliament.