Naomi Long was born on 13 December 1971, in east Belfast. She attended Bloomfield Collegiate and graduated from Queen's University Belfast with an Integrated Masters in Civil Engineering. She worked has worked as a consultant engineer and in research.

Long was first elected to Belfast City Council in 2001, representing the Alliance Party. In 2009, Long became Belfast's second female Lord Mayor. She served on Council until 2010.

In 2003, Long was elected to the Northern Ireland Assembly and served until July 2010. She was subsequently re-elected as a Member of the Assembly in May 2016. Long was named as deputy leader of the Alliance Party in 2006, and was elected as the party's leader in October 2016.

Long was elected as an MP in the 2010 Westminster election. She was the first MP elected to Westminster for the Alliance Party.