Finlayson joined the National Party in 1974 while still at St Patrick's College, after having had a long conversation with Keith Holyoake at Parliament the previous year.

Finlayson stood as National's candidate for the Mana electorate in the 2005 election, and was also ranked twenty-seventh on National's party list, making him the second most highly ranked National candidate who was not already an MP.
While he failed to win Mana, losing by a margin of 6,734 votes, the National Party polled well on party votes and Finlayson was elected via the party list.
Upon his election, he was appointed shadow Attorney-General by then leader Don Brash.
He had previously held the Shadow Cabinet roles of Shadow Attorney-General, Shadow Treaty Negotiations Minister and Shadow Arts, Culture and Heritage Minister.
And he was the Deputy Chairman of the Justice and Electoral Select Committee.

Following the election of John Key as leader, Finlayson was promoted to the Shadow Cabinet and placed at 14th on the 2008 election party list.
Since the 2008 election, Finlayson has contested the Rongotai electorate, which has been held by his cousin Annette King of the Labour Party since the 1996 election.

In June 2010 he was found by the registrar of pecuniary interests to have broken the rules in not declaring a directorship in his annual pecuniary interest return.

In the 2014 election, the National Party beat the Labour Party in the party vote in that electorate; the first time since the initial Rongotai election in 1996, as the Green Party gained over 25% of the party vote.

Following the 2014 election, Finlayson was appointed as the Minister Responsible for the Government Communications Security Bureau and the Minister in Charge of the New Zealand Security Intelligence Service, the country's two main intelligence agencies.
These positions had been traditionally held by the Prime Minister; instead, John Key assumed the newly created position of Minister of National Security and Intelligence.

After National lost the 2017 general election and became the main opposition party, Finlayson was appointed Shadow Attorney-General.

Finlayson left parliament in January 2019 after announcing his intention in November 2018.
He has said the highlights of his political career are:
2013 representing New Zealand in the International Court of Justice in a case against Japan's whaling programme.

2015: representing New Zealand on the United Nations Security Council in New York.

2008–2017: getting almost 60 Treaty settlements agreed.

After politics he intends to pursue work as a commercial arbitrator.
Finlayson joined the National Party in 1974 while still at St Patrick's College, after having had a long conversation with Keith Holyoake at Parliament the previous year.
Finlayson stood as National's candidate for the Mana electorate in the 2005 election, and was also ranked twenty-seventh on National's party list, making him the second most highly ranked National candidate who was not already an MP. While he failed to win Mana, losing by a margin of 6,734 votes, the National Party polled well on party votes and Finlayson was elected via the party list. Upon his election, he was appointed shadow Attorney-General by then leader Don Brash. He had previously held the Shadow Cabinet roles of Shadow Attorney-General, Shadow Treaty Negotiations Minister and Shadow Arts, Culture and Heritage Minister. And he was the Deputy Chairman of the Justice and Electoral Select Committee.
Following the election of John Key as leader, Finlayson was promoted to the Shadow Cabinet and placed at 14th on the 2008 election party list. Since the 2008 election, Finlayson has contested the Rongotai electorate, which has been held by his cousin Annette King of the Labour Party since the 1996 election.
In June 2010 he was found by the registrar of pecuniary interests to have broken the rules in not declaring a directorship in his annual pecuniary interest return.
In the 2014 election, the National Party beat the Labour Party in the party vote in that electorate; the first time since the initial Rongotai election in 1996, as the Green Party gained over 25% of the party vote. 
Following the 2014 election, Finlayson was appointed as the Minister Responsible for the Government Communications Security Bureau and the Minister in Charge of the New Zealand Security Intelligence Service, the country's two main intelligence agencies. These positions had been traditionally held by the Prime Minister; instead, John Key assumed the newly created position of Minister of National Security and Intelligence.
After National lost the 2017 general election and became the main opposition party, Finlayson was appointed Shadow Attorney-General.
Finlayson left parliament in January 2019 after announcing his intention in November 2018. He has said the highlights of his political career are:
2013 representing New Zealand in the International Court of Justice in a case against Japan's whaling programme.
2015: representing New Zealand on the United Nations Security Council in New York.
2008–2017: getting almost 60 Treaty settlements agreed.
After politics he intends to pursue work as a commercial arbitrator.
Chris Finlayson