He shows different social and political parts of society meeting and sometimes clashing,[1] his main characters range from lower-middle class to Prussian nobility.

Fontane is known as a writer of realism, not only because he was conscientious about the factual accuracy of details in fictional scenes, but also because he depicted his characters in terms of what they said or did and refrained from overtly imputing motives to them.

His biographer Gordon A. Craig claims that this gave few indications of being a gifted writer: "Although the theme of incest, which was to occupy Fontane on later occasions, is touched upon here, the mawkishness of the tale... is equalled by the lameness of its plot and the inertness of the style in which it is told, and [the characters] Clärchen and her brother are both so colourless that no one could have guessed that their creator had a future as a writer.

In order to provide for his family he accepted a job as a writer with the Prussian intelligence agency Zentralstelle für Presseangelegenheiten, which was intended to influence the press towards the German nationalist cause.

[11] While still in London he left his government job and on his return to Berlin became editor of the conservative newspaper Neue Preussische Zeitung.

As a man of liberal sympathies for free press and a united Germany Fontane ruefully wrote to a friend about his job with the Zeitung: "I sold myself to the reaction for thirty pieces of silver a month...

"[12] Fontane's travel books about Britain include Ein Sommer in London (A Summer in London, 1854), Aus England, Studien und Briefe (From England: Studies and Letters, 1860) and Jenseit des Tweed, Bilder und Briefe aus Schottland (Beyond the Tweed, Pictures and Letters from Scotland, 1860).

In his observations he strongly criticized Prussian militarism: "A mere glorification of the military without moral content or elevated aim is nauseating.

[18] His novels Irrungen, Wirrungen (Trials and Tribulations, 1888), Frau Jenny Treibel (1892) and Effi Briest (1894–95) yielded insights into the lives of the nobility and middle-class citizens.

In Der Stechlin (written 1895–97), his last completed novel, Fontane adapted the realistic methods and social criticism of contemporary French fiction to the conditions of Prussian life.

For example, in some novels including "Under the Pear Tree" and "Unwiederbringlich", there is mention of the Jewish heritage of a few key characters, as though this conveyed useful information to listeners (or perhaps readers).