Family and friends of a young footballer who died after an on-field head knock wore brightly coloured clothing to celebrate his joyous personality as they farewelled him in Adelaide.

Antonio Loiacono was honoured at a funeral on Thursday. The 20-year-old's family said he "always splashed his joyous personality on everyone he met".

"There have been many moments of sorrow, but even more moments of happiness and laughter as his friends and family have shared stories of his life. We are so blessed to have had such a happy kid," the family said in a statement.

"We have been in awe at the outpouring of love and support we've received since Antonio's death.

"We knew he was popular, but even we didn't understand the magnitude of his friendships. He always had a unique gift of belonging, closeness and uniting people."

Mr Loiacono died in hospital last month, a day after being knocked out while playing for the Birdwood Football Club in the A grade match against Gumeracha in the Hills Football League in South Australia.

The incident happened during the final quarter of the twilight game at the Gumeracha Oval. He was treated by paramedics at the scene and taken to hospital but his life support was turned off about 24 hours later.

The family said it had been Antonio's wish for his organs to be donated and they took comfort in knowing that in his death, others had been given the gift of life.

That included donating his brain to the Australian Sports Brain Bank to better understand concussions in amateur sports.

Born in Sydney, Mr Loiacono had suffered a number of head knocks playing football before his fatal injury.

Tributes included the Sydney Swans AFL team sending the family a guernsey signed by all the players.