Mourinho will front the upcoming campaign to promote the brand's Series shaving range, featuring TV and print activity, with images shot by fashion photographer Rankin.
The campaign will showcase Braun's premium men's electric shavers, including the Series 7 and Series 3.
Mourinho, the current Real Madrid coach, said Braun is a "brand with prestige".
He said: "They think I am good for their image. I also think being connected with Braun is good for my image. It’s a good partnership."
Braun executives view Mourinho's "calm authority" and "no nonsense attitude" as a natural fit for the brand.
James Nunn, grooming brand communications director at Braun, said: "We're extremely excited to have José Mourinho on board as a global ambassador for Braun, especially as he has such an affinity with our electric shaving products.
"He is a truly unique man, as evidenced by his timeless, individual style, unapologetic success and thoughtful ambition. Not only is he a leader in his field, but he is also an icon for men throughout the world."
In September last year, P&G claimed its Gillette ProGlide range would be the the biggest FMCG launch in the UK.