After the 2001 General Election Browne entered Tony Blair's government as the Parliamentary Under Secretary of State at the Northern Ireland Office.
He was promoted to Minister of State at the Department for Work and Pensions in 2003, before moving to the Home Office in 2004 as the minister with responsibility for immigration.
He joined the Cabinet following the 2005 General Election as the Chief Secretary to the Treasury and became a Member of the Privy Council.

Browne was appointed Secretary of State for Defence on 5 May 2006.
An advocate of the UK Trident programme, in 2007 he successfully persuaded Parliament to vote to replace Trident.
He came under criticism, however, after allowing the Royal Navy personnel captured by Iran in spring 2007 to sell and publish their stories.
Under Tony Blair's premiership, Browne was considered a supporter of the Chancellor of the Exchequer Gordon Brown.
He received the additional responsibilities of Secretary of State for Scotland in June 2007 after Brown became Prime Minister.

In a free parliamentary vote on 20 May 2008, Browne voted for cutting the upper limit for abortions from 24 to 12 weeks, along with two other Catholic cabinet ministers Ruth Kelly and Paul Murphy.
He returned to the backbenches in October 2008 following a cabinet reshuffle.

Browne gave evidence to the Iraq Inquiry on 25 January 2010.

Browne was created a life peer on 22 July 2010 taking the title Baron Browne of Ladyton, of Ladyton in Ayrshire and Arran.
After the 2001 General Election Browne entered Tony Blair's government as the Parliamentary Under Secretary of State at the Northern Ireland Office. He was promoted to Minister of State at the Department for Work and Pensions in 2003, before moving to the Home Office in 2004 as the minister with responsibility for immigration. He joined the Cabinet following the 2005 General Election as the Chief Secretary to the Treasury and became a Member of the Privy Council.
Browne was appointed Secretary of State for Defence on 5 May 2006. An advocate of the UK Trident programme, in 2007 he successfully persuaded Parliament to vote to replace Trident. He came under criticism, however, after allowing the Royal Navy personnel captured by Iran in spring 2007 to sell and publish their stories. Under Tony Blair's premiership, Browne was considered a supporter of the Chancellor of the Exchequer Gordon Brown. He received the additional responsibilities of Secretary of State for Scotland in June 2007 after Brown became Prime Minister.
In a free parliamentary vote on 20 May 2008, Browne voted for cutting the upper limit for abortions from 24 to 12 weeks, along with two other Catholic cabinet ministers Ruth Kelly and Paul Murphy. He returned to the backbenches in October 2008 following a cabinet reshuffle.
Browne gave evidence to the Iraq Inquiry on 25 January 2010.
Browne was created a life peer on 22 July 2010 taking the title Baron Browne of Ladyton, of Ladyton in Ayrshire and Arran.
Des Browne