Former goalkeeper Kahn was appointed in August and takes up his role from 1 January. He is due to succeed Karl-Heinz Rummenigge as the German club’s chairman at the end of 2021.
The 50-year-old made 632 competitive appearances during 14 years at Bayern, winning eight Bundesliga titles and the 2001 Champions League.
He retired in 2008 and became an award-winning pundit for German TV.
The former Germany captain also set up the Oliver Kahn Foundation to support socially disadvantaged young people.