Harrington, who has directly replaced MP Margot James as minister for pubs code policy*, announced he had stepped into the role in response to a fellow MP at a Westminster Hall debate on the pubs code.
The role is responsible for overseeing the enforcement of the pubs code.
He said: "I can confirm that I have the portfolio, only in the last few days, but I am responsible for pubs and will be responsible for pubs, I am listening very eagerly to what he and other honourable members are saying".
Harrington was appointed Parliamentary Under Secretary of State at the Department for Business, Energy and Industrial Strategy on 14 June 2017.
He served as Parliamentary Under Secretary of State at the Department for Work and Pensions from 17 July 2016 to 14 June 2017.
He was elected as Conservative MP for Watford in May 2010.
James was appointed Minister of State for the Department for Digital, Culture, Media and Sport in January 2018. Margot was previously Parliamentary Under Secretary of State at the Department for Business, Energy and Industrial Strategy from July 2016 to January 2018. She was elected Conservative MP for Stourbridge in May 2010.
In July 2010, The Morning Advertiser interviewed James, who said she wanted the beer tie to be "done away with".
Jake Berry, Conservative MP for Rossendale and Darwen was appointed pubs minister in July 2017.
Describing the job as a "hot ticket" among fellow MPs, Berry said he would ensure the sector was given his attention, despite his brief being wider than just pubs.
Berry replaced Andrew Percy in the latest Government reshuffle which saw him take over responsibility of the Northern Powerhouse, the same remit that Percy had held.
Berry's role looks more at community rights, and focuses on issues such as business rates.
Berry became an MP in 2010 and was appointed parliamentary under-secretary of state at the DCLG on 14 June 2017.
*The role was originally titled pubs policy minister, but was changed on 25 January.
- Additional reporting by Nikkie Sutton. Story updated on 25 January.