Geoffrey Chaucer (1343?-1400), during his life, worked as a page in a royal house, a soldier, a diplomat, and a royal clerk, according to the text book I use to teach Brit. Lit. (Prentice Hall).
Of course, his most well-known "job" was poet. For fun, here's a quote from John Gardner's The Life and Times of Chaucer:
IN 1374, IMMEDIATELY AFTER JOHN OF Gaunt's return to England from abroad, honors began falling to the poet thick and fast. On St. George's Day, the great time of religious and chivalric celebration for the Order of the Garter, the king granted him a pitcher of wine for life, a gift commuted in 1378 to cash. (204)
On a more serious note, as a soldier Chaucer was once captured and held for ransom, and the reigning monarch actually paid it.
Chaucer was many things in his life. Due to the connections of his father, he became a courtier (court worker) in the court of Edward III.
Chaucer is believed to have studied law, but he became a type of diplomat/bureaucrat in the court of Edward III and later, Richard II. He then became a comptroller (a financial position, similar to an accountant), so, to sum up, he was a government worker.
During these occupations, he was also writing. He wrote poetry and narratives and is considered the "father of the English literature" because he was the first one to write exclusively in the English language, not Latin, French or Italian, thereby establishing English as a worthy language for literature. He also wrote about philosophy.
Some of Chaucer's writing is quite risque, and he also translated some works into English. His most famous work, however, is The Cantebury Tales.
You can read about this work here on enotes.