Kessie, 25, has joined Barca on a four-year deal after his contract expired with Milan on June 30.
The Ivory Coast international’s move to Camp Nou ends his five-year stay at the Rossoneri where he made 224 appearances and scored 39 goals.
Kessie strengthens coach Xavi Hernandez’s options in midfield and will compete for a place in the team with Sergio Busquets, Pedri, Gavi and Nico Gonzalez.
However, club president Joan Laporta has said Barca have no intention in letting the Dutch international leave Camp Nou.
After moving to Italy with Atalanta in 2015 and following a loan spell with Cesena, Kessie joined Milan on loan in 2017 before making the move permanently in 2019.