Matsuo's training group results allowed him to enter the JSA's apprentice school at the rank of 6-kyū in March 1994 as a protegee of shogi professional Kazuharu Shoshi.

Matsuo won the 3-dan League in his first attempt and was officially awarded professional status and the rank of 4-dan on April 1, 1999.

[2] The promotion history of Matsuo is as follows:[3] Matsuo has yet to appear in a major title match, but he did defeat Kazuki Kimura two games to none to win the 32nd Shinjin-Ō [ja] tournament—a tournament for shogi professionals age 26 and under who are also ranked 6-dan or lower and are not currently a major title holder—in 2001.

[7] Mastuo married women's professional shogi player and fellow Shoshi protegee Kaori Uekawa in April 2005.

[8] However, the Ladies Professional Shogi-players' Association of Japan announced on December 1, 2014, that Uekawa would no longer be competing under the name "Matsuo".