Swedish novelist, critic, and short-story writer, noted for his elegant style and his ironic treatments of life's disappointments and inherent limitations.

Söderberg began his career as a civil servant but soon turned to writing, starting as a critic. His first novel, Förvillelser (1895), displays his characteristic irony, disillusionment with life, and a subdued compassion. His second novel, Martin Bircks ungdom (1901; Martin Birck's Youth), has much of the fin-de-siècle melancholy of the 1890s in it but is also one of the finest descriptions of childhood in Swedish literature. In this book Söderberg captured Stockholm's sights and sounds with an evocative poetry that had never been achieved before. His novel Doktor Glas (1905; Doctor Glas) caused a sensation because of its apparent justification of a deliberate ethical murder. His play Gertrud (1906) and his novel Den allvarsamma leken (1912; “The Serious Game”) are tragicomic treatments of the illusions of romantic love.

Söderberg was also a skillful short-story writer, the best known of his four collections being Historietter (1898). In these brief sketches, he mocks human complacency and self-deception in his terse, probing, witty style. After 1910 he lived mainly in Copenhagen.