Speaking on behalf of the family, celebrant K-M Adams described described an outgoing young man who was "annoyingly good at everything he did".
A talented sportsman, he used to run circles around everyone else on the soccer field.
He had just booked a ticket to the Gold Coast before he died.
"He'd said to the family, 'have you seen the girls there?' He was off to change the GC to the CC - the Connor Coast."
Connor liked girls and they chased him, she said But it was not to be.
"Connor was much loved by his family and friends. Nearly every Facebook post, and certainly every member of his family, mentioned something about his sense of humour, his cheekiness and that unforgettable smile."
Johnston's service will take place at Hamilton Gardens this afternoon.