He has watched his family friend, five-year-old Zac Franks, battle the cancer.
Zac was diagnosed with acute lymphoblastic leukaemia in 2011, and he is continuing with treatment that initially caused him to lose his hair.
He has since grown it back.
This inspired Lachlan, of Inglewood, to join in the World’s Greatest Shave and raise money for the Leukaemia Foundation.
‘I thought it would be nice to look for a cure for kids with leukaemia, like Zac,’ Lachlan said.
So far, the St Peter’s School student has raised just under $500 for the Foundation, with his target set at $1000, which he hopes to reach when he shaves his head in front of the entire school at assembly.
His mother Marnee said the idea was a year in the making.
Lachlan first suggested that he would like to do it last year, but didn’t have time to raise funds.
Zac’s mother Jody said her family thought it was a great idea.
‘He is such a brave boy,’ Jody said.
‘When I explained to Zac what Lachlan was doing, he said, ‘I’m going to keep my hair’.’
To donate, go to www.|worldsgreatestshave.com.