Now seven days in, he has already received hundreds of signatures and garnered the attention of the Rock Radio Station.
But ultimately, he has yet to catch the attention of the band.
"Meeting them would be pretty cool and being in the front row at the concert would be awesome too, though, I think I might get squashed."
And although his friends at Havelock North Intermediate don't share the same music, it is something the Year 7 takes in his stride.
"I'm kinda the odd-one out".
His favourite member of the band is now dead bass guitarist, Cliff Burton, describing him as "pretty awesome".
Father, Matt Bush said William and 15-year-old brother Ben both play the guitar and thought they would give Metallica a "hurry up".
"I think it's pretty cool. I doubt they will come here, but it gives him something positive to keep his mind on it and we will see what happens.
"They went to AC/DC when he was 3, so they've been into music a long time ... it doesn't matter who."
Hawke's Bay Today contacted Metallica's publicist for comment but they did not respond.
To sign the petition, visit: www.change.org/p/frontier-touring-help-bring-metallica-back-to-new-zealand