The real first name of the "Game of Thrones" character known as "Littlefinger" is Petyr. His full name is Petyr Baelish, a politically ambitious nobleman who rises from a minor house to become Master of Coin on King Robert I Baratheon's small council.
The nickname "Littlefinger" reflects both his physical size and his origins. Petyr came from a small holding in the Fingers, a group of rocky peninsulas in the Vale, and was smaller and less imposing than the young nobles around him. Edmure Tully gave him the nickname when Petyr was fostered at Riverrun with the Tully family.
Petyr is played by Irish actor Aidan Gillen in HBO's adaptation and first appears in the television series in the 2011 episode "Lord Snow." The spelling is also a common source of confusion: the character's name is officially "Petyr," not the ordinary real-world spelling "Peter." His talent for manipulation, bribery, and strategic alliances makes him one of Westeros's central schemers.