Mikel San José grew up in the Basque city of Pamplona and attended local academy, Txantrea, until making the switch to Lezama in 2005 when he was 16 years old. In 2007 he signed a contract with Liverpool where he joined the reserve team but never made it to the senior squad. He returned to Athletic on loan in 2009 and the move was made permanent the following season. Since his return to his boyhood club, San José has had several huge moments such as his goal from midfield against Barcelona in the Spanish Super Cup and being called up to represent the Spain National Team.
Mikel San José is under contract through 2020 and his deal contains a €40 million release clause.