In Parliament he served as a member of the Administration Select committee 1997–2001, and has been a member of the Foreign Affairs Select Committee since the 2001 general election.
He is also the chairman of the all party groups on business services, prison health, and civil contingency, he also serves as the vice-chairman of the all-party Iran group.
He also chairs the All-Party Parliamentary Group for Tibet.

On 7 January 2016, Hamilton was appointed a shadow Foreign Minister, outside the Shadow Cabinet.

On 29 June 2016, Hamilton was appointed as Shadow Europe Minister to replace Pat Glass, who resigned over concerns about Corbyn's leadership.
Hamilton resigned a few days later on 4 July 2016, saying that he was troubled by Corbyn's response to the Chakrabarti Inquiry into anti-Semitism.

On 8 November 2016, Corbyn fulfilled a campaign pledge as Hamilton was appointed as Shadow Minister for Peace and Disarmament - the first time this role had been held.
The role covers North Africa, the Middle East, North Korea and Labour Party policy on nuclear weapons.
When elected Leader of the Labour Party, Sir Keir Starmer kept the role as Shadow Minister for Peace and Disarmament, with Hamilton continuing in the role.
In Parliament he served as a member of the Administration Select committee 1997–2001, and has been a member of the Foreign Affairs Select Committee since the 2001 general election. He is also the chairman of the all party groups on business services, prison health, and civil contingency, he also serves as the vice-chairman of the all-party Iran group. He also chairs the All-Party Parliamentary Group for Tibet.
On 7 January 2016, Hamilton was appointed a shadow Foreign Minister, outside the Shadow Cabinet.
On 29 June 2016, Hamilton was appointed as Shadow Europe Minister to replace Pat Glass, who resigned over concerns about Corbyn's leadership. Hamilton resigned a few days later on 4 July 2016, saying that he was troubled by Corbyn's response to the Chakrabarti Inquiry into anti-Semitism.
On 8 November 2016, Corbyn fulfilled a campaign pledge as Hamilton was appointed as Shadow Minister for Peace and Disarmament - the first time this role had been held. The role covers North Africa, the Middle East, North Korea and Labour Party policy on nuclear weapons. When elected Leader of the Labour Party, Sir Keir Starmer kept the role as Shadow Minister for Peace and Disarmament, with Hamilton continuing in the role.
Fabian Hamilton