She was the eldest of Elisabeth Busch (née Elverfeldt)'s twelve children with her husband, magistrate Ignatz Anton Busch (a Stadtrichter and Landrichter). She grew up in Dülmen and was educated at Agnetenberg abbey. She spent 1807 to 1809 in Münster, where her literary talent was recognised and encouraged by Anton Matthias Sprickmann and where she also joined the circle of Adelheid Amalie Gallitzin. She returned to Dülmen in 1809.
She first published her poetry in 1810, in Friedrich Raßmann's Mimigardia. She had asked for the poems to be published anonymously, but the publisher did not respect her wishes and her name and residence were appended to them. This led to her being scorned and ridiculed but did not do permanent damage to her reputation as a poet – in 1813 she first met Annette von Droste-Hülshoff, becoming a close friend and thinking of her as her "poetic idol". Droste later dedicated her poem Catharine Schücking to her. Schücking later wrote under the pseudonym "Pauline zu Cl."
In 1813 she married Paulus Modestus Schücking. The couple had six children: Christoph Bernhard Levin Matthias (1814–1883); Peter August Gerhard (1816–1817); Anton Matthias Franz Alfred (1818–1898); Ida Josephina Theophania Desideria (1821–1883); Modesta Paulina Nicolaia Roswitha (1825–1896); and Prosper Ludwig (1828–1887). In 1815 the Schücking family moved to Sögel, leaving Katharina socially and geographically isolated and bringing her writing to a standstill.
(German) K. Weber: Katharina Schücking. Ein Erziehungs- und Lebensbild aus dem Anfang des neunzehnten Jahrhunderts. Diss. Münster 1918 [handschr.] (ULB Münster).
(German) Levin Schücking: Lebenserinnerungen. 2 Bde. Breslau 1886 – zahlr. Erwähnungen in der Literatur über Annette von Droste-Hülshoff, z.B. in Darstellungen von Elise von Hohenhausen und Elise Rüdiger.