[6][5] He was taken in by Pak Ch'an-myŏng (박찬명; 朴贊明), a local leader of the native Korean religion Donghak.

[6] In August 1905, he received a scholarship from the organization Iljinhoe to study abroad in Japan, and enrolled in the Daise Middle School (Japanese: 大城中學) in March 1906.

They intended to then go to the United States, where he was to be appointed lead writer of the newspaper Sinhan Minbo, but this plan was interrupted by the outbreak of the 1914–1918 First World War.

Through the paper, he published Korean literature and initially appeared to be a faithful member of the independence movement.

However, historian Michael Shin argues that Yi became increasingly viewed with skepticism by Korean nationalists over time.

In 1939, Yi became the first head of the pro-Japanese Korean Writers Association (朝鮮文人協會/조선문인협회) and lead intense efforts to Japanize (hwangminhwa) Korea.

After the war, the Special Committee for the Investigation of Anti-nationalist Activities found Yi guilty of collaboration.

In July 1910, Yi married for the first time at age 18, in what was possibly an arranged marriage to Paek Hye-sun (백혜순; 白惠順).

In late 1909, while at Meiji Gakuin, Yi published his first work of literature: a Japanese-language short story entitled "Is It Love" (Japanese: 愛か？).

[5][15] Around this time, he was reading the works of mostly Russian authors, including Alexander Pushkin, Maxim Gorky, and Leo Tolstoy.

[16] He also read a number of Japanese authors, including Tōson Shimazaki, Kenjirō Tokutomi, Kinoshita Naoe, and Natsume Sōseki.

[15] In November 1916, Yi published what is considered the first modern work of literary theory in Korea, which was entitled "What Is Literature" (문학이란 하오).

[17] His most famous work is now considered the first modern Korean novel: Mujeong [ko] (name sometimes translated as The Heartless).

[18] From the early 1920s to the 1930s, Yi transformed into a dedicated nationalist and published a controversial essay, "On the Remaking of National Consciousness", which advocated a moral overhaul of Korea and blamed Koreans for being defeatist.

In one famous case he befriended then abandoned the fellow writer Kim Myeong-sun, allegedly because his own beliefs about modernism had shifted.