From a FAQ on the storyline of SF:
Height: 196 cm
Weight: 103 kg
SF1 action: left hook
SF1-era nickname: “Killer Boxer with Godly Fists”
Street Fighter 1: Mike is the former heavyweight boxing champion. He got
kicked out of boxing because he killed someone in the ring. He now
participates in the Street Fighter 1 tournament in order to make some money
for a living, and to help his hospitalized little sister. [Official]
Where he is now: Contrary to what videogames.com stated, Capcom has never
remotely given any indication of what happened to Mike (sorta like how they
didn’t really give much definitive info about where Geki is). Got
knocked out by Joe possibly.
Miscellaneous Facts and Notes
Is Mike M. Bison? No. Mike was once a champion class boxer. Bison
continually aspired to become champion but never did. Also, Mike disappeared
from the boxing world after killing an opponent. Bison permanently injured
opponents but has only been known to have killed Kodal’s father (Kodal’s the
elephant Dhalsim rides in his SF2 ending).
Mike and Joe are rumored to be the fighters at the intros of SF2, SF2
Dash, and SF2 Dash Turbo, from Cap!#13 and the SF2 Gamest pre-mook. Rumored
because CJ has clarified neither that they are nor that they aren’t.
Taken from here: http://fightingstreet.com/folders/variousinfofolder/variousinfopages/streetfighterplotguide.txt