Mobile and app users click here to watch the video.
Applicants had to submit a video to The Warehouse Facebook page explaining why they would make a good toy tester.
The four winners each get $200 worth of toys every month for a year, their job to play, assess and rate the toys, giving feedback to The Warehouse's toy buying team.
The families of each tester also receive a cash prize of $8000.
Samuel's mum, Paulina Romero, said creating the video entry was a breeze.
"We did the video on Lego because it is Sammy's favourite toy. He is very eloquent and had no problem talking about Lego because it is what he loves."
Ms Romero said Samuel's passion for Lego was very clear in his video entry and could have been one of the reasons he was chosen.
"He has been playing with Lego since he was little and although he can follow the instructions to build things, what he really loves to do is create new structures and use his imagination."
Samuel said he had a plan for the toys he was given during the year, but won't use.
"With the toys I don't like, we're going to give them away for free to other children that don't have toys.
"I probably won't give away any of the Lego, though, because they will be my favourite."
Samuel said this was the best first job ever and when he grows up he wants to work at Lego.
"I would love to have the job where you can come up with new Lego creations."
The other winners are Chas Stensness, 6, from Tauranga, Evie MacDonald, 9, from Christchurch and Ella Garlick, 6, from Whangaparaoa.