Tadano joined the Theater Echo Training Institute in 1988, and two years later became a research student at the same entity.
[2] Dubbing assignments for western movies continued for some time, but from 2006 Tadano expanded into anime, first for Hime-sama Goyōjin.
For the 2009 TV dub of For a Few Dollars More, which restored scenes deleted from the 1973 theatrical cut, he was cast as Manco, replacing the late Yasuo Yamada.
A dubbing staff member heard Tadano's performance in Hime-sama Goyōjin and said, "There's a guy who sounds like Lupin!
He voiced Nucky Thompson in Boardwalk Empire and also performed as the comical villain King Candy in Wreck-It Ralph, Heinz Doofenshmirtz in Phineas and Ferb and Mr. Smee in Jake and the Never Land Pirates.