Reimertz was raised at his grandmothers in the medieval village of Niederwenigern on the Ruhr Peninsula, later attended school in Kronberg, where he joined the Catholic Boy Scouts.

His monograph on the German artist Max Beckmann connects structural analysis with a cultural historiographic narrative and is considered a benchmark in modern art history.

Reimertz’s first novel, Eine Liebe im Portrait ("A Love in Portraiture"), was released in 1996, featuring the fate of the artist Minna Tube, a painter who became a celebrated mezzo-soprano after her husband Max Beckmann had banned her from painting.

Reimertz set up a new style of Realroman ("reality novel"), using only authentic quotations and composing them in an artistic narrative structure, thus combining the French tradition of biographie romancée with the German classical forms of Künstlerroman and Bildungsroman.

In 2001, Stephan Reimertz authored Papiergewicht ("Paper Weight"), an autobiographical novel set in a decadent upper-class family, reflecting the social changes of the early Seventies.