Organisers were delighted with the success of the event after the tradition was revived after an absence of more than four decades.
Saturday's bash was arranged by the Garry Chappelow Memorial Fund which was set up after the tragic death of the Leeds Rhinos fan in 2002.
The day included an Under Nine rugby tournament – won by Hunslet Parkside – with a new Garry Chappelow Memorial Fund trophy and medals for the winners, maypole dancing by Woodlesford Primary School and Castleford Maypole and Dance.
Lord Mayor and Lady Mayoress of Leeds, Coun and Mrs Frank Robinson opened the event which also featured children's rides and police and fire displays.
Local bands the Bridewell Taxis and the Irregulars also entertained the crowds.
Event chairman Ray Blay said: "We were absolutely delighted with the turnout and the rain held off so everyone could have a great time as well as raise money for junior sport in Leeds.
"We are confident that we can now go on and make Children's Day an annual event once again."
Since it was launched in 2002 the Garry Chappelow Memorial Fund has raised more than £50,000 for junior sports clubs in the city by staging annual events including a Valentines Dance and Sportsman's Dinner.
As a youngster, Garry – who was 59 when he died after being hit by a car in East End Park – regularly attended Children's Day, which was held between 1922 and 1963.