José Müller was born in Lisbon on 22 February 2003 and is a product of Benfica's own academy, joining the under-15 set-up in 2016 and moving up through the under-17 and under-19 sides before reaching the under-23 team in 2021.

A tall central defender at 1.93 m, comfortable with either foot and occasionally used at left-back, Müller was promoted to the Benfica B squad for the 2023/24 season, his only campaign with the reserve side in the Liga Portugal 2. He did not appear for the first team.

He left Benfica in August 2024 for Famalicão, where he played principally for the under-23 side, and in January 2026 he moved abroad for the first time, signing with FC Lahti of Finland on a contract running to December 2027.