Doc Louis appears in both versions of Punch-Out!! for the NES( "Mike Tyson's Punch-Out!!" and "Punch-Out!! Featuring Mr.Dream") as Little Mac's trainer.
"The First Fight", a Nintendo Comic System strip, explains how Doc and Mac met. After Little Mac suffers a defeat at a local gym, Doc Louis encourages Mac to begin a comeback. Little Mac asks if Doc will train him, and that's just what he does. In the strip it also explains that Doc Louis was a Heavy Weight contender in the 50's.Punch-Out!!! (Nes)
Between rounds in the games, Doc offers Mac encouragement, advice, and even tries to persuade him to join the Nintendo Fun Club.
"Yes you can Mac!"
"Join the Nintendo fun club today Mac!"
"Dancing like a fly, bite like a mosquito!"
"Listen Mac! Dodge his punch then counter punch!"
" Watch His Left!"Punch-Out!! (Wii)
In Punch-Out!! for the Wii Doc Louis also makes an appearance to give you some advice between rounds. This advice ranges from slightly useful to completely useless. Doc is also a chocoholic, and is able to heal Mac in between rounds by using his chocolate candy bar.