1936—Alexander Harley and his wife Frances founded the Maine Music Masters at Maine Township High School in Park Ridge, IL.
1952—Maine Music Masters became incorporated and was renamed Modern Music Masters.
1954—The first individual member recognition, known as the Top-Notcher Certificate of Achievement, was presented. This certificate was renamed Tri-M® Leadership in 2002.
1971—First Master Musician Certificate was presented.
1983—Modern Music Masters became a program of MENC: The National Association for Music Education and was officially renamed the Tri-M Music Honor Society.
1986—The first year Tri-M was recognized by the National Association of Secondary School Principals (NASSP) as an approved program.
1989—The first State Conference Achievement Recognition was presented to Tri-M members accepted to All-State Honor Ensembles. This certificate was renamed Honor Ensemble Achievement in 2003.
2002—State Chapter of the Year recognition was given in addition to the National Chapter of the Year.
2002—The Top-Notcher Recognition was renamed Tri-M Leadership.
2003—The State Conference Achievement Recognition was renamed Honor Ensemble Achievement and was expanded to recognize Tri-M member participation in state, division, and national honor ensembles.
2003—The first Tri-M Outstanding Service Recognition was presented.
2004—The first Tri-M Alumni Achievement Recognition was presented.