Here's what I might add, having been an active tournament player during that 'era'... (keep in mind that was the '70s, and anyone who really lived at that time will have very limited -- perhaps even distorted -- memory of it for a variety of reasons

).
While I don't specifically recall that name, I can tell you that the traveling demo players/teams were employed by Tournament Soccer (the company that ran the main/featured pro tour in that decade). I do recall all the players/teams that did that, and Michael wasn't one of them. To verify 100%, contact Kathy Brainard (former TS employee and WTSF, USTSA and USTSF President: kbrain9999@aol.com). Having said that, during that time I did demos that weren't affiliated with TS, but for local distributors, retailers and pinball (later video) arcades, but not as part of touring the country -- so even if he wasn't employed by TS, he still may have done a few demos.
Kathy may also be able to dig up past ranking lists that would show if he was actually ranked pro or master. She has the most historical lists/files of anyone. I have many such lists as well, but they're in storage/not easily accessible.
Beyond that, the title "National Champion" covers a lot of people, in that it can apply to anyone having won any category at a National Championship tournament. That means it could have been in Open, Pro, Novice, or Rookie (the categories that were used back then) and in any of doubles, singles, mixed doubles, or specialty events such as goalie-war, forward shootout, draw-your-partner, and more. If he had won it in Open or Pro, it would ring a bell with me, but then again it WAS the '70s.
I still won't rule out his story, since there are probably two hundred or so pro and master players that used to tour but that are no longer listed in ratings/rankings lists or on website databases. Off the top of my head, here are a few great players from the '70s that haven't appeared in many rankings lists for about 25 or more years (in no particular order):
Randy Hutson (CO)
Mark Taylor (CO)
Don Becker (IL/CA)
Richard Loffredo (CO) ...yes, Todd's older brother was ranked as a pro player!
Sergio Trevino (CO) ...yes, Gus' older bro was a master player on TS, taking 2nd in a Super Singles to Dan Kaiser
Aaron Gilmore (WI/FL) ...yes, Amedio's older brother
Wally Hudson (IL)
John Myers (CO)
Tim Buchli (CO)
Bobby Benson (CO/TX)
Drew Stocker (CO/KY)
Edan Stachelek (CA) (Evan's brother)
Danny Sullivan (CA)
Jerry "JK" Knowles (IL)
George Petroheleos (IL)
"Dr. Bob" Thorud (IL)
Erwin Burke (CO)
Shawn Coonrod (MN)
Scott Bennis (MN)
Dan Kraus (WI)
Bob Maloney (CO)
Tim Burns (CO)
Alwood Mackekau (WA/OR)
Dave McWeeny (WA/OR)
Marcio Bonilla (WA/IL) and of course,
Doug Fury (pronounced Furry) (MN)
...and I'm sure if I put my mind to it (hazy as my memory is) I could easily come up with dozens more.
If you post this question elsewhere, I recommend you mention what state/city he lived in during that time, so as to bring focus to people's memories.
Hope that helps!!
Larry Davis, President
United States Table Soccer Federation
www.ustsf.org