A massive search was launched for the 16-year-old, who was found dead in a woodland near Banchory four months later.
His friends decided to hold an event in his memory, with scores of people turning out to cheer them on at a football tournament on Sunday.
They hit £6,000 that night, but that has now risen to £9,000.
All money raised goes to Mental Health Aberdeen who hope to fund a new youth counsellor.
The amount has been described as “staggering”.
Alison Reid, head teacher at Westhill Academy, said: “We’re so proud of the young people, the dedicated staff and the wider community who have supported this fundraising effort in Liam’s memory.
“We share lots of good memories of Liam and this charity football match was a great way to celebrate his life at the same time as supporting a very worthwhile cause.”
Headteacher praises Westhill pupils for fundraising effort in memory of Liam Smith