Smith was elected to the Dáil in the 2016 general election. She was elected to Dublin City Council in 2009 and 2014. She stood for the MEP elections for Dublin in 2014. Smith was involved in the campaign to repeal the Eighth Amendment and was a member of the Joint Oireachtas Committee on the Eighth Amendment to the Constitution. She has also been involved in protests against water charges and bin taxes in the early 2000s.