The product of his research, the 1984 book Development Studies and Capital Expenditure Economics, won the Suntory Liberal Arts Prize.

He taught as an associate professor at Osaka (1987–89) and Harvard (1989–90), and received tenure in the Faculty of Policy Management of Keio University SFC (Shonan Fujisawa Campus).

In this capacity, Takenaka has become one of the most prominent voices in the ongoing debate over the privatization and breakup of Japan Post.

One of his biggest accomplishments was to change attitudes within the financial industry, including auditors who had previously rubber-stamped bank earnings reports that understated the size of bad loans.

After Koizumi's Liberal Democratic Party crushing victory in the 2005 General Election, Takenaka assumed his last position as Minister of Internal Affairs and Communications, in charge of Japan Post privatization.