Luigi is a CPU Mii.
Wii Sports
In Tennis, his skill level is 3600. He teams up with Mario. In Baseball, his skill level is 1712. In Boxing, his level is 2000.
Wii Sports Resort
In Swordplay, his skill level is 11999. He is also the boss of Level 42 in Swordplay Showdown. In Basketball, his level is 11929 and plays with Mario and someone. In Table Tennis his level is 11999.