8th December 2017, 16:27 | Warrington
The Wolves have paid £45,000 for the 18-year-old England Academy international and included him in their 25-man first-team squad for 2018.
"I had the pleasure of coaching Luis as the England Academy head coach and was really impressed by his attitude, his understanding of the game and willingness to work and learn," said Warrington assistant coach Lee Briers.
"I see massive potential in him, he is definitely one to watch.
"His signing is a huge coup for the club and I am looking forward to working with him and watching him grow and develop into a Super League player."
Johnson helped Castleford reach the academy Grand Final and was named man of the series when England played France in two Tests in October.
"Luis is a great young talent who is held in high regard in the English rugby league community," said Warrington head coach Steve Price.
"We were attracted to him by his powerful attacking skills along with his strong, aggressive defence.
SQUAD NEWS | Castleford Tigers can confirm that youngster Luis Johnson has left the club. The 19 year old will join Warrington Wolves on 4 year deal. Read more here ➡️https://t.co/57xv2lxUrA pic.twitter.com/sUj74lm4n1— Castleford Tigers (@CTRLFC) December 8, 2017
"Luis will be a great addition to the 2018 squad and we still have the potential to bring in one more player."
Tigers head coach Daryl Powell admitted Warrington's bid was too good to turn down.
"We were recently approached by Warrington Wolves with an incredible offer for a young player and after taking a long time to consider their offer we decided to allow Luis Johnson to move to Warrington immediately," he said.
"We have taken into account Luis' wish to take up this offer and our significant depth and length of contract in the back row and felt it was best in both Luis' and our club's interests that we allowed him to further his career at the Wolves."