Magriel has finished in the money eight times at the World Series of Poker (WSOP), which includes one cash in the Main Event in 2010, he has also made the final table on the Professional Poker Tour and Ultimate Poker Challenge.
Magriel created the "M Principle" (better known since as the M-ratio) - a theory elaborated on at great length in the book Harrington on Hold'em Volume II by former WSOP Champion "Action" Dan Harrington and Bill Robertie.