The deal, announced Friday, begins from the 2019-2020 season and carries an average yearly price of $1.25 million.
The 27-year-old DeSmith is 12-7-4 with a 2.47 goals-against moderate and a .924 rescue percent for the Penguins. DeSmith began this season as the copy behind Matt Murray but played regularly during November and December while Murray managed a lower-body injury and inconsistent play.
General manager Jim Rutherford praised DeSmith for bettering under tough conditions. Throughout a 12-start stretch from Nov. 21-Dec. 31, DeSmith moved 8-3-1 to help the Penguins shake off a slow beginning to get straight back in the playoff picture from the crowded Metropolitan Division.
The signing also provides the Penguins equilibrium in goal on the brief term. Murray, a two-time Stanley Cup winner, is signed through the end of next season.