He established a climbing club while studying law at Keio University in Tokyo, from which he graduated in 1919.

[1] During the period 1919 to 1921, he made numerous climbs in Switzerland, and on 10 September 1921, he made the first ascent of the Eiger by the Mittellegigrat (northeast ridge) with mountain guides Fritz Amatter, Samuel Brawand and Fritz Steuri.

[1][3][4] In 1922, he made the first winter ascent of Mount Yari (3,180 metres (10,430 ft)) in Japan.

[1] In 1926, he was again in the Alps, making the ascent of the Matterhorn via the Zmuttgrat, and climbing with Prince Chichibu.

[1][6] Maki's climbing career was interrupted by World War II, preventing him from leading a Japanese expedition to the Himalayas.