[3] Of the hundreds of biographies and portraits he wrote for the newspaper, he published a selection of fifty obituaries in 1880 under the title Ur vår samtid ('From Our Time').

His Bilder och minnen ('Pictures and Memories') (1889) includes a parliamentary gallery (from Stockholms Dagblad) and obituaries (from Ny illustrerad tidning and the calendar Svea [sv]).

His perceptiveness in the fields of politics, learning and publicity, combined with a sympathetic outlook and a clear, smooth, and varied manner of presentation, made him particularly suited to the work of a biographer.

Wieselgren was a member of the board of the Swedish Fornskrift Society [sv] for a number of years, and in its Samlingar ('Collections') he published Helige Bernhards skrifter ('The Writings of Saint Bernard') (1855–1866).

In 1863, together with pathologist and fellow member of Sällskapet Idun Axel Key, he began a series of public lectures in the capital, which were subsequently taken over and conducted by a royal directorate until the state funding made available to it was withdrawn.

Fahlstedt writes: "W. is widely known and appreciated as a socialite with a never-ending sense of humor and a remarkable ability to perceive a situation at lightning speed and to illustrate it in the form of a speech, at once playful and meaningful, whereby the exemplification drew strength from his unusually extensive knowledge and memory.