Smith is also believed to have a limited no-trade clause as part of the deal.
It had been reported for a while that the Rangers and Smith were trying to work out a deal to keep the defenseman in New York.
The Rangers acquired Smith at the trade deadline for a third round pick in 2017 and a second round pick in 2018.
Adam Rotter: It's probably an extra-year and maybe $300,000 to $500,000 more than I thought Smith would get, but I'm guessing that the Rangers had to go a little higher to lock Smith in and prevent him from becoming a UFA. It's a workable deal for the Rangers and plugs one of the holes that they had on defense. Smith brings toughness and I wouldn't be shocked if he, like Kevin Klein and Nick Holden before him, produces more offensively than expected. Smith isn't a perfect player and probably had his toughest game as a Ranger at their most crucial moment, Game 6 against Ottawa, but he is a good fit for the Rangers and allows them to work on other moves to help fix the defense.