Third child of Thomas Mann, he was born Gottfried Angelus Mann in München, Bavaria.

He left Germany when Hitler came to power, left Europe when Hitler conquered it and eventually left America to return to Switzerland in 1958 and began to make a name for himself as a literary historian. His work was popular, although at times criticized for his unscientific, fictional approach. He was awarded numerous prizes including the West-German Goethe Prize.

He died in Leverkusen, North Rhine Westphalia.