Watford MP Richard Harrington will become parliamentary under-secretary for pensions, replacing pensions minister Ros Altmann, who left the government on Friday.
The Department for Work and Pensions (DWP) confirmed that while Harrington's title was different from his predecessor's, responsibilities and the policy brief remained the same.
He will report directly to DWP secretary Damian Green, who was hired to replace Stephen Crabb.
One of Harrington's responsibilities will be to work on a new Pensions Bill, which was announced as part of the Queen’s speech to strengthen the regulation of master trusts schemes.
He said: "I am delighted to take responsibility for this important ministerial post, and I look forward to tackling the full range of state and private pension matters, including the new Bill and automatic enrolment, among so many others."
Harrington has been an MP since the 2010 general election. In September 2015, he was appointed as parliamentary under-secretary for Syrian refugees jointly at the Home Office, the Department for International Development and the Department for Communities and Local Government.
Prior to this, Harrington was a member of the International Development Select Committee.