On his election as Lord Mayor of Dublin, Councillor Dermot Lacey became a Commissioner of Irish Lights ex officio. He took the oath and his seat on the Board on 27 September 2002.

After his Leaving Certificate Dermot Lacey joined the Labour Party and worked in the hotel, printing, and building industries. Following a period of unemployment in the 1980s he worked for five years as Manager of a Community Employment Initiative. He now works for the Labour Party as Development Officer with responsibility for liaising with Local Authority members.

Councillor Lacey represented the South Inner City on Dublin City Council from 1993 to 1999. Since then he has represented the Pembroke area. He is Chair of the Strategic Policy Committee for Arts, Culture, and Leisure, and a member of the Corporate Policy Group and the City Development Board since 1999.

Through his involvement in the scouting movement and Labour Youth Councillor Lacey was on the Board of the National Youth Council of Ireland for many years, with four years as Vice-President and three as International Chairperson. At present he represents youth interests on the Board of FÁS.

He is a member of Clan na Gael Fontenoys GAA Club, Dublin Civic Trust, Burma Action Ireland, Old Dublin Society, Irish Labour History Society, and SIPTU.