He was born in Hanau, Germany and in 1803 he started studying law at the University of Marburg, one year after his brother Jakob did the same.
In 1825 Wilhelm married Henriette Dorothea Wild, also known as Dortchen.
From 1837-1841 the Grimm Brothers joined five of their colleague professors at the University of Göttingen to form a group known as the Göttinger Sieben (The Göttingen Seven). They protested against Ernst August, King of Hanover, whom they accused of violating the constitution. All seven were fired by the king.