Smith, 31, had been the current longest-serving member of the Senators after being selected 79th overall in the 2008 NHL draft.
The native of Maple Creek, Sask., scored 94 goals and 193 points in 612 career regular-season games with Ottawa.
Smith, who was placed on waivers last September only to go unclaimed by the league’s other 30 teams, added nine points (two goals, seven assists) in 45 playoff contests. He registered nine goals and 28 points for the rebuilding Senators in 2018-19.
Anisimov, also 31, had 15 goals and 37 points in 78 games with Chicago last season. In 703 career outings with the Blackhawks, New York Rangers and Columbus Blue Jackets, the native of Yaroslavl, Russia, has put up 163 goals and 347 points.
The 54th pick in the 2006 draft by the Rangers has added eight goals and nine assists in 43 playoff games.
The move for Anisimov adds both depth down the middle in the nation’s capital and pushes the Senators over to the NHL’s salary cap floor of $60.2 million.
Smith has two years left on a contract that carries an annual average value of US$3.25 million, while Anisimov’s current deal also runs through 2020-21 with an AAV of $4.55 million, according to capfriendly.com.
Anisimov immediately becomes the second-highest paid forward on Ottawa’s active roster behind Bobby Ryan and his $7.25-million cap hit.
Including the combined $9.525 million owed to injured wingers Marian Gaborik and Clarke MacArthur in 2019-20, Ottawa’s wage bill for next season is currently projected at $60.86 million, with restricted free agent centre Colin White still in need of a new contract.