jubilant

joyful and proud especially because of triumph or success

Uttering songs of triumph; shouting with joy; triumphant; exulting.

Latin 'jubilare' to shout for joy

“Prophetic of the coming joy and strife, Like the wild western war-chief sinking Calm to the end he eyes unblinking, Her voice is jubilant in ebbing life.”

— George Meredith, Complete Project Gutenberg Works of George Meredith

“On 7 December 1941, Ribbentrop was jubilant at the news of the Japanese attack on Pearl Harbor and did his utmost to support a declaration of war on the United States.”