David entered local Government in 1991 after winning the local by-election for the Castle district. During that time he served as Deputy Mayor from 1994 – 1996, and 1997 - 1998 he was elected as Mayor and again from 2004 – 2008.
David was first elected as a Member of the Northern Ireland Assembly in 1998, re-elected in 2003, 2007, 2011, 2016 and most recently in 2017. David currently sits on the Infrastructure and Public Accounts Committees.
David is also a member on numerous All-Party groups, including Sports and Physical Recreation, Football, Cycling, Animal Welfare and reducing harm related to gambling.