A versatile striker and attacking midfielder, Menyongar's first tryst with India was with United Sikkim in the second division before he signed for Shillong Lajong in the I-League for the 2011-12 season.
The 33-year-old's last switch was a loan move to Goan team Dempo last season.
"I am extremely happy to sign with JSW and am looking forward to giving my best this season. I was very impressed with the club's plans for the future and wanted to be a part of this professional set up. My main focus will be to train well and have a successful season," said Menyongar after signing the deal.
"John is the kind of player who can be expected to create goal scoring chances as well as score. He is bound to bring a lot to the team," said Pradhyum Reddy, assistant coach at JSW Sports.
While Arvind Narayan, Libero Sports Partner and Menyongar's FIFA Licensed player agent, said, "Menyongar is a quality player and will be a great addition to JSW Sports. He will help JSW Sports in their quest for winning titles on all fronts.