The previous council was controlled by the Conservatives, with the Liberal Democrats being the only opposition.
They won the seat for Forncett Ward, which had been vacant since the death of the Conservative councillor Hedley Smith in January 2011.
Overall the Liberal Democrats polled a lower vote-share in South Norfolk overall.
Their vote-share dropped by almost 10%, with half of the votes going to Labour and the rest to the Conservatives, the Green Party and UKIP.
In Cringleford and Wymondham Rustens the Lib Dems finished in 4th place behind Labour and the Greens.