He was born in 1877 in Kanazawa, Ishikawa Prefecture under the name Ohara Matao. He studied painting and drawing with Suzuki Koson whose name he adopted later.
He started with illustrations of the Russo-Japanese war in 1904-1905. It was the time when the art of traditional prints (Ukiyo-e) was no longer in vogue, replaced by photography. Many artists of these years had great success with these wartime prints. Koson was then teaching at the Tokyo School of Fine Arts where an American colleague, Ernest Fenellosa (1853-1908) persuaded him to return to printmaking in the traditional style. His first prints of flowers and birds were published by Daikokuya (Matsuki Heikichi), Kokkeido (Akiyama Buemon) and Nishinomiya Yosaku.
From 1912, he devoted himself to painting under the name "Shoson" and returned to printmaking only in 1926 with the publisher Watanabe Shosaburo, the initiator of the Shin Hanga (or pictorial revival) movement. Most of these prints were exported to the American market.
Koson's prints are close to watercolors and are made with great care and attention to detail, especially on the feathers.
Ohara Koson used different seals and signatures during his career and it is very difficult to date his works precisely. The prints made after the great Kanto earthquake of 1923 are generally more vivid in color than his early works. Some were printed with different color variations.