Friedrich Schiller was born on 10 November 1759, in Marbach, Württemberg, as the only son of military doctor Johann Kaspar Schiller (1733–1796) and Elisabeth Dorothea Kodweiß (1732–1802). They also had five daughters, including Christophine, the eldest. Schiller grew up in a very religious family and spent much of his youth studying the Bible, which would later influence his writing for the theatre. His father was away in the Seven Years' War when Friedrich was born. He was named after king Frederick the Great, but he was called Fritz by nearly everyone. Kaspar Schiller was rarely home during the war, but he did manage to visit the family once in a while. His wife and children also visited him occasionally wherever he happened to be stationed. When the war ended in 1763, Schiller's father became a recruiting officer and was stationed in Schwäbisch Gmünd. The family moved with him. Due to the high cost of living—especially the rent—the family moved to the nearby Lorch.
Although the family was happy in Lorch, Schiller's father found his work unsatisfying. He sometimes took his son with him. In Lorch, Schiller received his primary education. The quality of the lessons was fairly bad, and Friedrich regularly cut class with his older sister. Because his parents wanted Schiller to become a pastor, they had the pastor of the village instruct the boy in Latin and Greek. Pastor Moser was a good teacher, and later Schiller named the cleric in his first play Die Räuber (The Robbers) after him. As a boy, Schiller was excited by the idea of becoming a cleric and often put on black robes and pretended to preach.
In 1766, the family left Lorch for the Duke of Württemberg's principal residence, Ludwigsburg. Schiller's father had not been paid for three years, and the family had been living on their savings but could no longer afford to do so. So Kaspar Schiller took an assignment to the garrison in Ludwigsburg.
There the Schiller boy came to the attention of Karl Eugen, Duke of Württemberg. He entered the Karlsschule Stuttgart (an elite military academy founded by the Duke), in 1773, where he eventually studied medicine. During most of his short life, he suffered from illnesses that he tried to cure himself.
While at the Karlsschule, Schiller read Rousseau and Goethe and discussed Classical ideals with his classmates. At school, he wrote his first play, The Robbers, which dramatizes the conflict between two aristocratic brothers: the elder, Karl Moor, leads a group of rebellious students into the Bohemian forest where they become Robin Hood-like bandits, while Franz Moor, the younger brother, schemes to inherit his father's considerable estate. The play's critique of social corruption and its affirmation of proto-revolutionary republican ideals astounded its original audience. Schiller became an overnight sensation. Later, Schiller would be made an honorary member of the French Republic because of this play. The play was inspired by Leisewitz' earlier play Julius of Tarent, a favourite of the young Schiller.