The free agent first baseman with the bushy beard reached agreement with the World Series champions Friday on a two-year contract for $32 million.
Napoli tweeted that "The beard is coming back to Boston!!! Couldn't be happier!!"
Napoli hit .259 with 23 home runs and 92 RBIs this year in his first season with the Red Sox.
The 32-year-old Napoli drove in a total of seven runs during the postseason as Boston beat Tampa Bay in the division series, defeated Detroit in the AL championship series and topped St. Louis to win the championship.
Napoli left Texas as a free agent after the 2012 season and reached agreement with the Red Sox on a three-year deal for $39 million. But it was later discovered that Napoli, a catcher for most of his career, had a condition in both hips that can cause bone tissue to die because of poor bloody supply.
The Red Sox and Napoli altered the deal to a one-year contract for a base salary of $5 million — with incentive bonuses, Napoli wound up making $13 million.
With this new contract, Napoli is set to earn $45 million for three years with the Red Sox, up $6 million from the original deal the sides reached.
Napoli was a smooth fit for the Red Sox his year, part of their beard brigade that made them so popular on and off the field.
His power was a welcome addition, as was his approach. He never griped when slugger David Ortiz moved from designated hitter to start at first base during the three World Series games in St. Louis that were played without the DH.
Napoli returned to the lineup for Game 6 and hit an RBI single in the clinching 6-1 win.