[2] He was promoted to 1-dan in 2007[2] and participated in the 3-dan League for the first time in April 2008,[3] finishing with a record of 13 wins and 5 losses.
[3][5] In October 2012, Nagase won his first tournament since turning professional when he defeated Shingo Itō 2 games to none to win the 2nd Kakogawa Seiryū Tournament [ja],[6] and followed that up by defeating Tetsuya Fujimori a few days later to win the 43rd Shinjin-Ō [ja] by the score of 2 games to 1.
[13] Nagase, however, was unable to capture his first major title, losing the match to Wantabe 3 games to 2 in March 2018.
[22] In September–October 2021, Nagase successfully defended his Ōza title by defeating Kazuki Kimura 3 games to 1.
[23] In June – July 2022, Nagase challenged Sōta Fujii for the 93rd Kisei title, but lost the match 3 games to 1.
[31] Nagase received the JSA's Annual Shogi Award for "Most Consecutive Games Won" in 2011 and 2013.