Sammy began his life in politics as the Democratic Unionist Party’s Press Officer and in 1981 he was elected as a DUP Councillor to Belfast City Council, a position he held until 2010. Sammy became the first person from the DUP Party to serve as Lord Mayor of Belfast in 1986/1987 and then again in 2000/2001.
Sammy was elected to the Northern Ireland Forum in May 1996 for the Constituency of East Belfast (1996-1998) and went on to represent this area again after he was elected to the Northern Ireland Assembly upon its creation in June 1998. In the 2003 Assembly elections, Sammy stood as a candidate in the East Antrim constituency alongside fellow DUP candidates, George Dawson and David Hilditch. All three were successful in the election and served as Members of the Legislative Assembly.
On 9 June 2008, Sammy became part of the Assembly Executive as Minister for the Environment. His appointment and tenure as Environment Minister were heavily criticised by Environmental Groups because Sammy believes that climate change is not man-made and the myth of climate change is based on dodgy science not proven. He is not a fan of the Green Lobby who try to scaremonger people with their alarmist views.
In June 2009 after an Executive reshuffle, Sammy became the Minister for Finance and Personnel. He was replaced as the Minister of Finance and Personnel, again after a planned reshuffle by Simon Hamilton MLA in 2013. During his time in the Northern Ireland Assembly Sammy also served on the Northern Policing Board and the Education Committee.
In the 2005 Westminster Elections Sammy defeated Roy Beggs of the Ulster Unionist Party to become the Member of Parliament for East Antrim with 49.6% of the vote.
In 2016 coming up to the referendum on Brexit, Sammy campaigned vigorously for the United Kingdom to leave the EU and believes that the country would be better served being in charge of our own finances, trade and immigration laws. He serves on the Brexit Committee at Westminster.
Away from politics, Sammy is a keen motorbike enthusiast, a keen gardener, he is an ardent reader and is well known for his sense of humour.