Royal Borough councillors were called to an extraordinary meeting at Maidenhead Town Hall to attend the inauguration of 32-year-old Cllr James Evans (Con, Clewer South).
The Cambridge graduate took up the position following the shock resignation of Cllr John Lenton (Con, Horton and Wraysbury) last month.
Cllr Natasha Airey (Con, Park) nominated Cllr Evans and took the opportunity to explain the work he already undertakes within the community.
This includes his involvement with Age Concern and his role as a governor of Hilltop First School in Windsor.
He is also chairman of the Royal Borough's Cycling Forum.
The motion received a majority vote.
Cllr Evans was thanked for stepping into the role at short notice and sworn in by Royal Borough managing director Mike McGaughrin.
James, who has lived in the Royal Borough for his whole life, was first elected as a councillor at the age of 25.
He will service until the end of the municipal year on May 20.
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