William was the younger brother of George IV. He was known as the 'Sailor King' due to his time serving in the Americas in the Royal Navy as a young man. He had left the Navy before the French Revolutionary and Napoleonic Wars and sought to be returned to active duty. This was avoided by his father, King William IVI, although he was given more ceremonial duties within the Navy. Given his experience in Naval matters, he was appointed Lord High Admiral in 1827. In this post he abolished the cat o' nine tails for most offences other than mutiny; he attempted to improve the standard of naval gunnery and he required regular reports on the condition and preparedness of each and every ship. Most importantly of all, he commissioned the first steam warship and lobbied for their rapid construction and integration. This modernist view of the Royal Navy often put him at odds with the Admiralty who were more conservative and complacent in their views after their recent victory over the French.
As King, he was a conscientious worker who was felt to be more approachable than his predecessors. He anglicised much of the Royal household by replacing French chefs, German musicians by British equivalents. He presided over great political turmoil as the Great Reform Act was pushed into place with his reluctant consent. This would do much to extend the franchise and democracy in Britain which would have profound effects over the rest of the Century. In imperial matters, he signed the law that abolished slavery throughout the British Empire. He generally did not get along with the activist policies of Palmerston who was his foreign secretary for much of his reign. He reluctantly agreed to the extension of local powers for Canada. His instinct was that the introduction of more democracy might lead to the loss of this colony much as the 13 colonies had been lost to his father. However, he had no choice but to follow the advice of his prime minister Melbourne. This shows just how little power was left to the monarch when it came to matters of policy.
He lived just long enough to ensure that his niece, Victoria, would come to the throne at 18 without the need for a messy regency. William was not King for long, but it was an eventful period as Britain started to enter a much more liberal phase in its history.