After suffering significant damage during the battle from more than 3,000 artillery rounds over 34 hours, at 2:30 p.m the following day Major Anderson and his men formally surrendered, and the Confederate forces took control of Fort Sumter.

Walpole was appointed First Lord of the Treasury, Chancellor of the Exchequer and Leader of the House of Commons. This made him the de facto Prime Minister and, while the title was not officially recognized at the time, Walpole wielded considerable power and influence.