One of a small cadre of Asian actors of the TV studio system who, because of their comparative rarity, actually seemed to play a wider range of types than most character actors of the time. Of course they were also viewed as interchangeable, with Japanese, Chinese, Korean and other Asian actors playing all of these and other nationalities pretty much arbitrarily. Soon-Taik in particular fell outside the more egregious prevailing stereotypes, however, and brought some real nuance to his parts.

So, no shtick, unless you count his distinctive, almost torchy, voice.