Willi Heinrich was born in Heidelberg, Baden-Württemberg, and during the Second World War he fought the Russians in the Eastern Front with the 1st Battalion 228th Jäger Regiment of the 101st Jäger Division, the infantry unit of the characters of Das Geduldige Fleisch (The Willing Flesh; Cross of Iron), his most famous novel. In the war's course, the 101st Jäger Division suffered seven hundred per cent casualties; Heinrich was wounded five times.

After the war, Heinrich became a writer; his first novel, In einem Schloss zu wohnen, written 1950—1952, went unpublished until 1976, when he was an established novelist. His first commercial novel, Das Geduldige Fleisch (The Willing Flesh), was published in 1955, and almost immediately was translated to English and published as The Willing Flesh (1956), by Weidenfield & Nicolson in the U.K., and as Cross of Iron (1957), by Bobbs-Merrill in the U.S. To date, the novel remains in print and in many editions; in 1977, Sam Peckinpah cinematically adapted it as Cross of Iron, featuring James Coburn as the protagonist anti-hero "Steiner".

Though he began as a war genre novelist, Heinrich concentrated in the potboiler genre of soapy, sexy stories that were very popular in the 1970s and 1980s. Most of his books are novels, but Erzählungen (1985) is an anthology comprising three novellas: (i) Die Freundinnen, (ii) Fata Morgana, and (iii) Harte Bandagen. His last book, Der Gesang Der Sirenen [The Singing of the Sirens], was published in 1994 when he already was retired; Willi Heinrich died in Dobel, near Karlsruhe, in 2005.