The Conservatives have regained the seat that they lost to the Greens four years ago in Withdean.
Nick Taylor, 24, a postgraduate at the London School of Economics, won the third seat for the Conservatives, defeating Green councillor Sue Shanks.
Conservative councillors Ann and Ken Norman held their seats.
Sue Shanks said: “You win some, you lose some.”
Withdean
(3 seats)
Leo Barraclough, Labour, 2,170
Beth Granter, Trade Unionist and Socialist Coalition, 210
Steve Griffiths, Green, 1,932
Hyder Khalil, Liberal Democrat, 560
Jamie Lloyd, Green, 1,864
Juliet McCaffery, Labour, 2,552
Michael Middleton, Labour, 2,145
Ann Norman*, Conservative, 3,495
Ken Norman*, Conservative, 3,348
Sue Shanks*, Green, 2,189
Nick Taylor, Conservative, 2,985
Turnout was 76.48 per cent and 45 ballot papers were rejected.