Bradley Lowery's mum read out an emotional poem honouring the life of the little fighter as he was laid to rest.
Gemma Lowery called him an inspiration for his brave battle with cancer neuroblastoma.
In the poem she said: "A smile so big and beautiful it could brighten any room.
"A real brave superhero who left us far too soon.
"He touched the hearts of many, the most inspirational boy by far.
"A loving, caring son and good brother, a beautiful star.
"Although your time with us was short, you must have a job to do.
"In heaven with the angels, as God has chosen you.
"Our lives and hearts are broken, way beyond repair.
"When looking for some comfort for each other we'll be there.
"For now my baby we'll say goodbye,
"We'll meet again my superhero high up in the sky."
The six-year-old, who touched the hearts of the world with his brave battle with neuroblastoma, was laid to rest at St Joseph's Roman Catholic Church today.
Crowds lined the streets of Blackhall in their thousands as they turned out to say their last goodbyes to little fighter.
Mourners wore football strips from various teams including Sunderland and Everton - a reference to the message championed by the youngster that #cancerhasnocolours -which trended on Twitter.
They held red, white and blue balloons with loving messages to Bradley, many which bore the words 'fly high Bradley Lowery.'
Sunderland fan Bradley was the mascot for Sunderland, Everton and England and his bravery in the face of the disease touched the hearts of the football community.
The cortege, which was headed by a police escort and bagpiper, saw a horse-drawn glass carriage carry the youngster's red and white Sunderland AFC coffin down Blackhall's Coast Road.
The family party followed by car and mourners wearing football strips followed on foot and by coach.
As the cortege made its way to the church, the crowds gathered applauded and chanted 'There's Only One Bradley Lowery.'
Bradley's favourite superheroes Batman, Wonder Woman, Spiderman and Captain America, provided a guard of honour for the brave boy as his coffin was carried into the church to Elvis Presley's 'Can't Help Falling in Love.'
Former Sunderland striker Jermain Defoe, who was wearing an England shirt, was among the mourners who attended the service.
Known as Bradley's 'best friend,' Jermain flew back from a training camp in Spain yesterday to attend.
He was joined by fellow players and representatives from the club including legends Kevin Ball and Jimmy Montgomery.
Following Gemma's reading, the congregation joined together to sing 'You Are My Sunshine' with the heart-breaking lyric, 'please don't take my sunshine away.'
A second poem called 'When God Saw You Getting Tired' was then read.
The poem made reference to Bradley's incredibly brave fight against his terminal cancer when it said: "And when I saw you sleeping,
"So peaceful and free from pain
"I could not wish you back
"To suffer that again."
Father Ian Jackson leading the service then read a eulogy of Bradley's life in which he told the story of his battle.
He said: "Little Bradley was born in the hospital of Hartlepool on May 17, 2011.
"When he was very small he attended the nursery at Blackhall Primary School and managed a full year in reception.
"He absolutely loved school.
"In the January 2013 when he was only 18 months old he was diagnosed with neuroblastoma, cancer of the nervous system, and began receiving treatment.
"Because of his wonderful little personality he managed to bring attention to childhood cancer and became a real celebrity, touching the lives of so many people.
"Over these past years many people have been helped simply because of Brad.
"He was a bright, loving, cheeky little monkey, he loved cuddles.
"He was warm and embracing and he touched the lives of us all."
A photo montage of Bradley's life was then displayed to the song 'One Call Away' song by by Charlie Puth.
A third poem called 'Laugh Again' was then read before the charity single - 'Smile for Bradley' - by sisters Olivia Crawford and Georgia Fletcher, known as Liv'n'G, was then played, with the heartbreaking last line sung by Bradley himself.
Mourners then left the church to the song, with Defoe getting into the family car.
Those lining the streets then applauded as Bradley's coffin was carried out of the church and placed in a car with white flowers spelling out 'hero.'
There was later a private family cremation.