Because he was fluent in English, Takeshita was posted overseas at various times as a naval attaché. In October 1902, he was appointed Japan's naval attaché to the United States. In this role, Takeshita was an active participant in negotiations mediated by President Theodore Roosevelt that led to the Treaty of Portsmouth, ending the Russo-Japanese War. During 1904, he also helped Roosevelt obtain the services of judo teacher Yamashita Yoshitsugu, first for Roosevelt himself and then for the United States Naval Academy. Takeshita's commands included the cruisers "Suma", "Kasuga", "Izumo", "Tsukuba" and the battleship "Shikishima".