Willemoes was born on 11 May 1783 in Assens on the island of Funen, where his father was a public servant.

After the battle, Willemoes became a member of the Danish Order of Freemasons before setting off to the Mediterranean Sea aboard the frigate Rota.

[2] After the 1807 Battle of Copenhagen where the British captured most of the Dano-Norwegian navy, he returned to Denmark, where he enrolled on Prinds Christian Frederik, the only remaining Danish ship-of-the-line.

On 22 March 1808, in the Battle of Zealand Point, the ship was driven onto a sandbar in order to prevent its capture by the British.

Willemoes was among the 69 Danish casualties, hit by a bullet to his head, and was afterwards buried at Odden Cemetery.