“Well done for trying hard… I have given you a gold star,” Harry’s letter reads, which is accompanied by a drawing of Rashford and a golden sticker.
“Don’t listen to nasty bullys. I love you. I have sent you my (trophy) to cheer you up.”
Harry has not yet sent the trophy, which he earned playing football himself, as he is self-isolating for two weeks – but his parents said he will when he can go to the post office.
James and Ruth Knox said they had tried to switch off news and radio reports about the racist abuse aimed at Rashford and his teammates Bukayo Saka and Jadon Sancho after their penalty misses in Sunday’s Euro 2020 final.
However, their son had started asking questions after seeing the Newsround report.
“He heard the word racist and we had to tell him what that was,” Mr Knox told the PA news agency.
“He couldn’t understand how people could be so horrible to the people he felt were heroes, and were playing and trying their best for him and England.
“What was really horrible is that his class at school is quite diverse.
“This was the first time he had given a second thought really of race and skin colour and how people might be ‘bullied’ in his words because of that.”
Mr Knox said his son is a “sensitive and kind lad” and was already aware of what Rashford “had done for children worse off than himself”.
Asked how it felt having to explain racism to his young son, Mr Knox said: “It’s horrible that the first time he realises there is a difference is when this is going on.
“(It) must be horrendous for other BAME families and kids right now having to have the same conversation.”
Harry is one of many children to write to Rashford and his teammates following England’s Euro 2020 defeat with dozens of letters sent on social media.
“It’s great, it’s probably for similar reasons and makes me hope that we are raising kids with compassion and better values than those adults who would send racist abuse,” Mr Knox said.