Radetzky March relates the stories of three generations of the Trotta family, professional Austro-Hungarian soldiers and career bureaucrats of Slovenian origin — from their zenith during the empire to the nadir and breakup of that world during and after the First World War. In 1859, the Austrian Empire (1804–67) was fighting the Second War of Italian Independence (29 April – 11 July 1859), against French and Italian belligerents: Napoleon III of France, the Emperor of the French, and the Kingdom of Piedmont-Sardinia.
In northern Italy, during the Battle of Solferino (24 June 1859), the well-intentioned, but blundering, Emperor Franz Joseph I, is almost killed. To thwart snipers, Infantry Lieutenant Trotta topples the Emperor from his horse. The Emperor awards Lt. Trotta the Order of Maria Theresa and ennobles him. Elevation to the nobility ultimately leads to the Trotta family's ruination, paralleling the imperial collapse of Austria-Hungary (1867–1918).

Following his social elevation Lt. Trotta, now Baron Trotta, is regarded by his family — including his father — as a man of superior quality. Although he does not assume the airs of a social superior, everyone from the new baron's old life perceives him as a changed person, as a nobleman. The perceptions and expectations of society eventually compel his reluctant integration into the aristocracy, a class amongst whom he feels temperamentally uncomfortable.