He starred in several movies throughout the 1980s, but his most famous role would be that of "Chairman Kaga", the eccentric and flamboyant host of Ryōri no Tetsujin, a cooking competition show (1993–1999).
The host of Iron Chef America, Mark Dacascos, is claimed on ICA to be Takeshi's nephew, though the stated relationship is actually between the fictional characters played by the two men.
He reprised his role as Valjean in 1995 as the representative of Japan during the encore of the 10th Anniversary Concert of Les Misérables at the Royal Albert Hall in London.
In 2005, Kaga performed as the lead in the Japanese production of Michael Frayn's Democracy and starred in the blockbuster film Sengoku Jieitai 1549.
Kaga also appeared in both installments of the highly successful Death Note film series as Soichiro Yagami.