The 25-year-old arrived in Italy in 2016 from Lech Poznan, and played 132 matches for Sampdoria, scoring 11 goals.
He also carried the colors of the Polish national football team in 23 international matches.
“The Turin club is pleased to announce the permanent contract with Sampdoria player Carol Linetti,” Turin said in a statement.
Italian press reports indicated that the transfer value of Linetti amounted to 7.5 million euros plus bonuses.
The player underwent a traditional medical examination and signed a contract until 2024 with La Granata.
Turin finished 16th in the Italian league last season, behind Sampdoria.