First-time MP Jared O'Mara was among a small group celebrating a great result for Labour on the steps of Town Hall this afternoon.
A small group - about 100 people - gathered to celebrate the party's 31-seat gain in Thursday's election.
Among them was Mr O'Mara, who ousted Nick Clegg from his Sheffield Hallam seat.
It was a shock result for the seat, so much so that Mr O'Mara reportedly had to run to Tesco to buy a new suit when the result became clear.
Mr O'Mara said the hard work started after the counting was finished.
"Just because it's the day after the election, you don't stop campaigning," Mr O'Mara said.
"I'm so glad we've not rested on our laurels, and that everybody has come out the day after the election," he said.
"This is day one. This is where it starts, and there's a lot of hard work to be done."
Joining Mr O'Mara this afternoon were representatives of Sheffield Trade Union Council, the People's Assembly, Stand up to Racism, Unison and the National Union of teachers.
Tomorrow, there will be another demonstration in the city, for the Sheffield Stands United Against Terrorism.
Sheffield muslims, led by Asif Akram and Rizwan Ullah, have organised the demonstration.
It will take place at Sheffield City Hall at 3pm.
A joint statement by the two men said they were against recent attacks in the country.
"As muslims, we stand united against the murder and carnage that has been committed in our country during the last few days," the statement read.
"Not only do we unequivocally condemn it, we stand united in solidarity with those who lost their loved ones and we stand united resolutely and firmly against the evil ideology of ISIS and their ideological sympathisers."