William Godley, who attends St Ebbe's School, helped out the Rt Rev John Pritchard with a service to mark the Diamond Wedding Anniversary of the Queen and the Duke of Edinburgh at Christ Church Cathedral last week.
A special invitation went out to Oxfordshire couples who married the same year to attend the service.
William's temporary elevation was part of '11 MILLION takeover day', when children across the country were invited to take over for a day.
The day - held last Friday 23 - is an initiative of the Children's Commissioner for England, Professor Sir Albert Aynsley-Green, as a way of making sure the voices of England's 11 million children and young people are heard.
Bishop Pritchard said: "We can all learn from an exercise such as this. What better way to find out whether we are giving our children what they need to grow and become the leaders of tomorrow than to let them show us the way.
"I shall be listening hard to what they tell us."
Two teenagers from Wargrave, Rachel Perry and Tim Creedon, also attended the service with the Bishop of Dorchester, the Rt Rev Colin Fletcher, after spending the day with him at a conference.
Other churches took part in the initiative by allowing children to plan and lead Sunday worship.
In St John the Baptist, Bodicote, and St Matthew's, Oxford, last Sunday's services were conducted by the young people of the congregation.
In Dorchester Abbey, two teenagers are preaching a sermon this Sunday, prepared with the help of their grandfather, and other young people will be involved elsewhere in the service.
Yvonne Morris, Children's Adviser for the Diocese, said: "This day offers an excellent opportunity to challenge the expectations and perceptions adults have of children and young people."
Sir Aynsley-Green said: "At a time when there is so much demonisation of children and young people in our society, it is important to appreciate that of course the vast majority of them make a hugely positive contribution.
"There are times when the ways in which children are represented are unfairly negative and 11 MILLION Takeover Day allows their qualities to come to the forefront, gives them the chance to take their rightful positions as valued members of society and is a great opportunity for organisations across England to show just how important children and young people are."
