The 27-year-old Eintracht captain has been a key player at Commerzbank-Arena since his move from Bayer Leverkusen in 2009, but has opted for a new challenge at the end of the season.
Having plied his trade almost solely in the Bundesliga since arriving in Germany from Young Boys eight years ago, Schwegler will now move to the Rhein-Neckar Arena on a three-year contract.
Hoffenheim director of football Alexander Rosen believes Schwegler will prove to be a shrewd signing.
"Pirmin's a player who has already proved his quality at a high level," he told the club's official website.
"He's a model professional with leadership qualities and one who'll be able to make a real impression on this young team on and off the pitch."
Schwegler, who could add to his 14 international caps at the FIFA World Cup later this year, said: "Hoffenheim follow a clear philosophy and play fantastic attacking football.
"That's what convinced me to take on this challenge and make this exciting move to Hoffenheim."
