Born to a wealthy family in Munich, he moved to London in 1900 to train as a financier, but took up photography and rapidly achieved great success.
In the era before the first World War, Hoppé photographed many leading literary subjects and figures from the art world, such as Henry James, Rudyard Kipling, John Masefield, Léon Bakst, Anna Pavlova, Tamara Karsavina and other dancers of the Ballets Russes, Violet Hunt, Richard Strauss, Jacob Epstein and William Nicholson, some of whom were included in his 1913 exhibition.
Other subjects of the 1920s included Albert Einstein, Benito Mussolini, Robert Frost, Aldous Huxley, George Bernard Shaw and A.A. Milne.
In the 1930s Hoppé photographed a number of dancers at the Vic-Wells company including Margot Fonteyn, Ninette de Valois, Hermione Darnborough and Beatrice Appleyard.
In 1913 he took on a lease of 7 Cromwell Place, occupying all thirty-three rooms of the previous home of Sir John Everett Millais, which later (from 1937) was used by dance photographer Gordon Anthony and subsequently Francis Bacon.
His journeys brought him to Africa, Germany, Poland, Romania, Czechoslovakia, the United States, Cuba, Jamaica and the West Indies, Australia, New Zealand, Japan, Indonesia, Singapore, Malaya, India and Ceylon.