Councillor Maggie Barradell, Labour and Co-operative member for East Brighton, is standing down for family reasons.
Ms Barradell was elected as a first time Councillor in East Brighton ward at the local elections in 2015.
Cllr Barradell said: “I feel really sad to be leaving the city but I know it is the right thing to do. My father died before Christmas and I need to return to Suffolk to look after my mum.
I leave with many fond memories and have been privileged to be a part of some really exciting plans to move the city forward. We will of course be back as holidaymakers as we were before we moved here.”
Leader of the Labour and Co-operative Group Councillor Warren Morgan said: “We will be very sorry to lose Maggie. Her contribution to the ward, to the Labour & Co-operative Group and to the city council has been immense even in a relatively short period. However family must come first, and I wish Maggie all the very best for the future.”
A by-election to replace Cllr Barradell will be called shortly to elect a new councillor for East Brighton.