Irwin was born on a small farm at Clough near Ballymena. He attended Ballymena Academy before moving to Belfast College of Business Studies and the University of Ulster, where he completed his accountancy studies and qualified as a Chartered Management Accountant and then a Fellow of the Institute.
Irwin worked in industry for several years before joining the Northern Ireland Development Agency, where he was involved on many International manufacturing projects. When the agency was absorbed into the civil service he left to set up a Management Consultancy specialising in Finance and Marketing.
Irwin has been involved in the start up of several businesses and in 2005 he founded CIGA Healthcare, specialising in Rapid Test Diagnostics.
Irwin has been a member of the Conservative Party since 1997 and is currently a member of the Executive in Northern Ireland, Chairman of Business Relations in Northern Ireland and a member of the Conservatives and Unionists Joint Committee.
He is married with two sons.
Profile based on information supplied by the party.