The 14-time Swiss international midfielder will join up with his new team-mates in the summer after penning a three-year deal at the WIRSOL Rhein-Neckar-Arena.
"Pirmin's a player who has already proved his quality at a high level," explained 1899 sporting director Alexander Rosen. "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."
For his part, Schwegler was only too happy to answer the Eagles' call. "Hoffenheim follow a clear philosophy and play fantastic attacking football," said the 27-year-old. "That's what convinced me to take on this challenge and make this exciting move to Hoffenheim."
Third Bundesliga station
The Ettiswil native first arrived on the Bundesliga scene in 2006 when he joined Bayer 04 Leverkusen from Swiss outfit BSC Young Boys. Three years later he moved to Frankfurt, where he later became team captain, scoring six goals in 127 appearances for the club.
Schwegler's last game in a Frankfurt shirt will be away to FC Augsburg on the final day of the 2013/14 campaign on Saturday.