In 1891, his father King Gojong issued a decree naming Yi "Prince Uihwa" with the style of Royal Highness.

[8] Yun Chi-ho, who met Yi before going Europe, assessed him as a smart 18 years old who had a good personality like his father but whom worried to study abroad.

[9] In August 1895, Yi was appointed as Special ambassador and visited some European countries including, the United Kingdom, Germany, France, Russia, Italy and Austria-Hungary.

[11] At the same year, he went to the United States and began studies at Roanoke College in Salem, Virginia from March 1901, where he majored in mathematics.

Also, Imperial Consort Sunheon bribed Itō Hirobumi, who was the Japanese Resident General of Korea, to appoint her son as the crown prince.

[22] When Itō Hirobumi was assassinated by An Jung-geun, Yi was ordered to participate the funeral as deputy of Korean Imperial House.

[24] Following the abdication of Emperor Gojong in 1907, and the Japan-Korea Treaty of 1910 by which Korea was annexed to the Empire of Japan, Prince Yi Kang grew increasingly dissatisfied with his status, even though the Japanese provided him with a huge annual allowance.

At the same time, the title "Prince Imperial Ui" was abolished and also received a reduction in rank to Duke by Japanese until 1930.

After the escape of Gim Ga-jin, an Imperial Korean official before, the Provisional Government's objective was Yi's refuge to Shanghai.

[27] On 9 November 1919, he collaborated with Choe Ik-hwan, a member of Daedongdan [ko], who attempted to support him as the new leader of Korea.

Prince Yi Kang then tried to escape to the Provisional Government of Korea based in Shanghai, only to be discovered in Dandong from Manchuria and returned to his home country.

With the help of Cheon Un-boek, who was an employee of the Japanese General Government Building, Yi successfully met Lee Jong-Wook, who came to rescue him.

[39] Yi said that the reason why he was baptized a Roman Catholic was to apologize for the Anti-Catholic of Joseon led by Heungseon Daewongun.

[43] Prince Imperial Ui, Yi Kang married Kim Deok-su (22 December 1880 – 14 January 1964) in 1892; however, the couple had no children.