Hundreds of people gathered at the Holy Trinity Church in Rothwell for the private service for Evan Hawksworth.
Evan, 14, who played for Stanley Rangers RLFC in Wakefield, suffered a head injury during a game against Batley Boys and died later in hospital.
Family members arrived at the church on Tuesday afternoon in two funeral cars, following a black hearse.
Floral tributes spelt out the words "Grandson" and "Evan", while one, in the shape of a rugby ball, had a card from family that read: "To us, you were so special, someone good and true. We will never forget you, we thought the world of you."
Crowds of mourners, all wearing colourful clothing, including rugby shirts, followed the coffin, which was covered in photographs of Evan, into the church for the service.
After Evan's death, his father Gary said: "Evan passed away playing the game he loved.
"He was never without a rugby ball in his hands.
"This is a tragic, freak accident and no-one is to blame."
Stanley Rangers paid tribute to the "fantastic lad" and tributes poured in on social media from other rugby league clubs.
Evan's school, The Rodillian Academy, in Lofthouse, said the teenager was "an outstanding sportsman" who captained his school's rugby union team from year seven onwards, winning a host of awards and being selected to be part of the year eight County Cup Final rugby squad when in year seven.
He was players' player of the year when he was in year seven and was awarded coaches' player of the year in year eight.
This year, Evan received the school's prestigious sports personality of the year award at its annual sports presentation awards.