Raster was born in Zerbst, in the Duchy of Anhalt-Dessau on May 6, 1827 to a family of aristocrats. He was the son of statesman Wilhelm Christian Raster, a personal friend of Leopold IV, Duke of Anhalt who served as the chief Collector of Customs and Excise for the Duchy and was a noted translator of the English language. His father insisted he learn English from a young age and had a tutor brought from England to instruct him. A naturally talented linguist, Raster was fluent in seven languages by the time he completed his education. He graduated from the University of Leipzig in 1846 and then the University of Berlin in 1848, studying philology, linguistics, and history at his father's behest. Despite his father's wishes for him to pursue a career in philology, the young Raster was interested in journalism and politics. In 1849 he took a position as the stenographer of the Anhalt Legislature and shortly thereafter was named Secretary of the State Assembly of Dessau. Spurred by an encounter with the writer Bettina von Arnim, he was involved with the German liberal political scene of the late 1840s, and passionately wrote pamphlets criticizing the church and state. In 1851, during the aftermath of the failed revolutions, he was given the choice to leave Germany or face trial for his actions.