Takachiho's first test of combat came during the First Sino-Japanese War of 1894-1895. At the Battle of the Yalu River on September 17, 1894, the Imperial Japanese Navy engaged the Qing dynasty's Beiyang Fleet in one of the most consequential naval battles of the nineteenth century. Takachiho played a major role in the engagement, which ended in a decisive Japanese victory and announced Japan's arrival as a serious naval power. She went on to participate in the Battles of Port Arthur and Weihaiwei, the Pescadores Campaign, and the invasion of Taiwan. For a single ship, it was an extraordinary range of action across the breadth of a war that redrew the map of East Asia.

When the Russo-Japanese War erupted in 1904, Takachiho was already two decades old, but she returned to service. She participated in the Battle of Chemulpo Bay, helped blockade Port Arthur at the war's opening, assisted in sinking a Russian armored cruiser during the Battle off Ulsan, and took part in the decisive Battle of Tsushima in May 1905, the engagement that destroyed the Imperial Russian Navy's Baltic Fleet after its epic voyage halfway around the world. By the time the war ended, Takachiho had fought in more major engagements than most ships see in a lifetime. But age was catching up. After the war, she was relegated to auxiliary duty, serving as a depot ship and training vessel before being converted into a minelayer in 1911.

World War I found Takachiho in her final role. Japan, allied with Britain against Germany, besieged the German-held port of Tsingtao, modern-day Qingdao, on China's Shandong Peninsula. On the night of October 17, 1914, while participating in the naval blockade, Takachiho was struck by two torpedoes fired by the German torpedo boat S-90. The old cruiser, her hull weakened by three decades of service, could not withstand the blast. She sank quickly, and most of her crew went down with her. It was a bitter end for a vessel that had survived the great fleet battles of two wars only to be lost to a single torpedo from a small boat in a minor siege.

Takachiho's career spanned the entire arc of Japan's transformation from a feudal island nation into an industrial and military power capable of defeating the established empires of China and Russia. She was commissioned when Japan could not build its own warships. She was sunk in a war where Japan fought as an equal ally of the British Empire. Between those bookends, she participated in battles that shaped the modern history of East Asia: the fall of the Qing navy, the humiliation of Tsarist Russia, and the seizure of German colonial possessions in China. Her crew members, the men who served aboard her through three decades, lived through changes as dramatic as any in modern history. Most of those aboard when she went down off Tsingtao never returned.