He attended a school that taught western-style painting, under the tutelage of Soyama Yukihiko. In 1891, he became a member of the "Meiji Bijutsu-kai" (Fine Arts Society) and, after Soyama's premature death, worked with Horie Moriaki, completing his studies in 1893.
That same year, he came under the influence of Kuroda Seiki and Kume Keiichiro, who had just returned from France. They introduced him the Barbizon school and the concept of plein-air painting. In 1896, he became an Assistant Professor of Yoga art at the Tokyo Bijutsu Gakko. He was also one of the founding members of "Hakuba-kai" (White Horse Society); a loosely organized artists' association, supposedly named after their favorite type of sake.
Later, the Ministry of Culture awarded him a stipend to study in France, where he worked with Raphaël Collin. When he returned in 1902, he was named a full Professor. After 1907, he served as a juror for the annual art exhibition held by the Ministry (the "Mombusho Tenrankai"). In 1912, he and Fujishima Takeji founded the "Hongo Institute for Western Painting". Seven years later, he was elected a member of the "Teikoku Bijutsu-in" (Imperial Academy of Fine Arts) and was awarded the Order of the Sacred Treasure.
In 1930, the Ministry of Culture sent him to Europe to speak with Hasegawa Kiyoshi and explore the possibility of staging an exhibition of modern Japanese art. Four years later, he was appointed an Imperial Household Artist.
In 1937, Okada received the Order of Culture, the highest honor in the Japanese cultural world. Overall, his art career showed an unusually smooth progression. Okada's painting subjects included both landscapes and portraits, and he was especially good at painting portraits of women. Under his brush, women were portrayed with warm skin textures, elegant features, and delicate traits. In 1907 he won the first prize of the Tokyo Industrial Exhibition for Image of a Woman (Purple tone). Later, he exhibited Women in Red, Japanese Bush Clover, Portrait of Marquess Ookuma's Wife, establishing his reputation in painting portraits of women.
In addition to his work in painting, he also studied applied art and collected many handicrafts, such as porcelain and glass, in his house.
He married the daughter of playwright Osanai Kaoru.