Gary is a CPU Mii.
Wii Sports
In Tennis his level is -1 nonillion (30 zeros) and plays with Alli or a duplicate of himself who is equally bad. In Baseball his level is -5 trillon (12 zeros) and plays with 8 duplicates. In Boxing, surprisingly, his level is 1.
Wii Sports Resort
In Swordplay Duel, his level is -9 quadrillon (15 zeros) and you can defeat him by pressing (A) or (2) when you face him. In Speed Slice he has the same level, and it takes him 1 hour to slice 1 object. In Basketball, his level is -65 quintillon (18 zeros) and plays with two Gary duplicates. In Table Tennis, his level is -90. In Showdown his level is -1 googol (100 Zeros)
Wii Sports Club
In Boxing his grade is Grade ★-1 decillion (33 zeroes). His grade in Bowling is -★900 decillion (33 zeroes).
Trivia
Gary is not very smart. He flunked kindergarten because he did not know what his name was. He also was expelled from First Grade because he could not figure out what 1+1 is. It's surprising he even made it to First Grade.
He had to retake first grade 14 times, and he had to retake 2nd grade 31 times until he finally passed (he got a D). He is in 3rd grade now, which he had to retake 5 times prior to this date. Gary is one of the worst Miis. He is also the laziest.
It is predicted that he will graduate high school in 2090.