The 24-year-old forward has one season remaining on a three-year, $4.2 million contract ($1.4 million AAV) he signed with Buffalo on Oct. 5, 2020. He set NHL career highs in goals (38), assists (30) and points (68) in 78 games last season.
"Obviously it's a really rewarding feeling just all the work that not too many people have gotten to see go on behind the scenes the past four or five years," Thompson said on "Sabres Live" on Friday. "It's a big leap of faith by ownership and staff and now it's just my job to continue to progress as a player and as a person and earn that contract and make it worthwhile."
Thompson said talks began with the Sabres not long after last season ended, and he was confident a contract would be completed before training camp opens later this month.
"I think Buffalo is a place that I want to be," he said. "I know my wife loves it there. Just a place that we want to be, get grounded there, build our family. On the ice, help this team make the playoffs and hopefully win the Stanley Cup. I think the talks started around May and as the summer progressed got a little more serious."
Selected by the St. Louis Blues in the first round (No. 26) of the 2016 NHL Draft, Thompson has 103 points (56 goals, 47 assists) in 223 regular-season games with the Blues and Sabres.
Thompson was acquired by Buffalo in the trade for forward Ryan O'Reilly on July 1, 2018.
"Tage Thompson embodies the pride we expect from every player who wears the Buffalo Sabres sweater," Sabres general manager Kevyn Adams said Tuesday. "His success last season is a testament to his unrelenting dedication to his craft and commitment to bettering the team both on and off the ice, which we believe will help us reach even greater heights moving forward."