Ken Takaseki won the Karajan Competition in Japan in 1977 while he was still a student at the Toho Gakuen School of Music.
After graduating from the school the following year, he left Japan to study at the Berlin Philharmonic Orchestra Academy (Karajan Foundation) and worked as an assistant to Herbert von Karajan till 1985. During the summer of 1981, he studied under Leonard Bernstein and Seiji Ozawa at  Tanglewood Festival. In the same year, he made his debut in Europe with the Bergen Symphony Orchestra in Norway.

In 1983 he won the second prize at the Nicolai Malco Competition for Young Conductors, and in 1984 he drew attention when he won the Hans Swarowsky Competition. In January the next year, he made his debut in Japan with the Japan Philharmonic Symphony Orchestra at its subscription concert. In 1991 he conducted the NHK Symphony Orchestra at its subscription concert and received outstanding critical acclaim. In 1994, he toured around Europe with the Gunma Symphony Orchestra with great success performing in various places and on such occasions as Prague Spring International Music Festival and Festival of Vienna.

Besides many orchestras in Japan, he has performed with Vienna Symphony Orchestra, Oslo Philharmonic Orchestra, ,Bergen Symphony Orchestra, Denmark National Radio Symphony Orchestra, Deutche Symphonie Orchester Berlin, Klangforum Wien, and WDR Symphonie Orchester Koeln among others. In 1994, he toured around Europe with the Gunma Symphony Orchestra with great success. In February 2013, he conducted a subscription concert of the St.Petersburg Philharmonic Orchestra, bringing out a full, rich sound from this distinguished Russian orchestra and receiving high praise from the audience and orchestra members.

His opera conducting career includes Mozart’s DIE ZAUBERFLÖTE (1990, 2007), LE NOZZE DI FIGARO (1991) and Monteverdi/Henze’s IL RITOMO d’ULISSE IN PATRIA (2009) with Tokyo Nikikai, Verdi’s FALSTAFF at a subscription concert of Gunma Symphony Orchestra (2003), Britten’s CURLEW RIVER at Sumida Triphony Hall (1997) and PETER GRIMES with The College Opera House, Osaka (2013) and Dan’s YUZURU at New National Theatre Tokyo (2011).

He was Music Director and Principal Conductor of the Hiroshima Symphony Orchestra (1986-1990); Conductor of the New Japan Philharmonic Orchestra (1994-2000); Principal Conductor of the Century Orchestra Osaka (1997-2003); Music Director for the Gunma Symphony Orchestra (1993-2008); Resident Conductor for the Sapporo Symphony Orchestra (2003-2012); and Principal Guest Conductor of the Kyoto Symphony Orchestra (April 2014- ).

He won Akeo Watanabe Foundation Music Award in 1996, and Hideo Saito Memorial Fund Award in 2011.

He is a professor for conducting department, faculty of music of Tokyo University of the Arts.
Takaseki was appointed Principal Conductor of the Tokyo City  Philharmonic Orchestra from April 2015.