Three judges, at least one from overseas - according to the rules - inspect the shearing inside the shed as well as out.
Judging convener Peter Black says they look for wool left on and any skin cuts when judging.
A lot of hard work and organisation goes into setting a record.
"Shearing a record is quite a selfish thing, it's a lot of dedication," Mr Mullins says.
That includes a strict training regime - swimming, the gym, physio - and lots of shearing.
He says: "Anyone that does a record in general is partly crazy, but it does take a lot of guts and it does take a lot of organisation to get something like this off the ground."
Not only do the men have to shear sheep on the day, but rules stipulate they must work together as a gang for three weeks prior to their attempt.
Supporters and spectators flocked from all over to watch history being made.
Dannevirke shearing business owner Mavis Mullens says shearing events such as these add "huge mana," and not just to the shearing fraternity, "but to the whole primary sector".
Eru Weeds and James Mack are previous world record holders.
But - it's Luke Mullins' first title - and a dream come true.