Jay tweeted out his reaction Tuesday night.
Jay owns the highest fielding percentage (.996) of any active center fielder and provides a left-handed complement to rookie righty Albert Almora Jr., who's also known as a defensive whiz.
The Cubs and Jay began talking about a deal at the GM meetings days after the World Series as the team stressed the need for the right fit in the clubhouse.
"One of the things that I respected is that the Cubs made it clear they are careful about the players they go after and recruit," Jay's agent, Nez Balelo, told ESPN. "The Cubs have built a chemistry over the past two seasons they believe has helped them evolve into a winner.I believe Jon Jay checked all of their boxes."
The signing could mark the end of Dexter Fowler's career in Chicago. The free-agent outfielder is expected to receive a multiyear deal elsewhere.
Jay, meanwhile, joins Almora, Kyle Schwarber, Jason Heyward, Ben Zobrist and Jorge Soler, the holdovers from a Cubs outfield that won the World Series. Zobrist moved to the outfield when Javier Baez took over at second base down the stretch.
One or more of the above-mentioned players could be on the move before the end of the winter as the Cubs continue to search for young, controllable pitching.