The team announced the signing Friday.
The extension includes $47 million guaranteed for Landry, according to NFL Network. Landry was acquired by the Browns in a trade last month with the Miami Dolphins. Cleveland sent a fourth-round pick (123rd overall) in 2018 NFL Draft and a seventh-round selection in 2019 to Miami.
"I'm excited for the journey with my new teammates and building, one day at a time, starting with the offseason program on Monday," Landry said in a statement. "Let's be great Cleveland."
A three-time Pro Bowl selection, Landry led the league in receptions with 112 last season. By comparison, the sum total of Browns receivers recorded just 134 -- with Rashard Higgins and Ricardo Louis each grabbing 27.
Landry finished with 987 yards receiving for an 8.8-yard average per catch in 2017. He also had nine touchdown catches.
The Browns have Josh Gordon at receiver, but off-field issues make his availability an issue. Corey Coleman, a first-round draft pick in 2016, had 23 receptions for 305 yards in nine games last season.