I just saw something on the net that made me calculate. It seems that Ed Boon is currently the leading actor in video games for voicing a character for soon to be more than 20 years.
If I count his voicework of Get over here! thn he has overtaken Joseph D Kucan, the actor of kane in the Command & Conquer games - my personal favourite RTS series and the game that got me gaming.
Though Kucan still holds first place if we count on screen acting. BTW you should really check out his work, both as Kane and both as a Director of Dramatic assets - shameless schilling here.