He poured out one of 10 bags, each containing about 4,000 pieces featuring classic scenes from Disney films such as The Jungle Book, Peter Pan, Bambi Fantasia The Lion King and The Little Mermaid and set his iPhone timer.
"The hardest one is Fantasia. It took me seven days and 53 hours," he told CBS Boston.
Brait, who previously completed the world's largest jigsaw puzzle with 32,256 pieces in 2014, finally completed the Ravensburger puzzle on Nov. 5 after 80 days and 423 hours.
"I'm the first American born person to complete more than two of the biggest puzzles in the world," he said.
Brait, who has autism, began building puzzles when he was 3 years old and said his autism has helped him excel at completing the world's largest puzzles.
"My autism helps me put the pieces together because my mind looks at the image a lot and connects the pieces all together," he said.
Brait and his family placed the puzzle in a custom-built wall that hangs in their basement.
"If they get any bigger, I'll need a bigger house," his mother Michele said.
Brait's 2014 record-breaking puzzle now sits in a corridor in his former middle school where he hopes it will inspire others.
"Although I have a disability I can still do many things," he said.
