Classes initially held in the tabernacle owned by the Church of Jesus Christ of Latter-day Saints, but by 1906 a dedicated white brick building was completed for the high school.

In February 1980 the building where the high school currently stands on the north end of Manti was completed.

[1] The tradition of having an "M" representing the high school on the mountain likely originated in an attempt to imitate the "Y" for Brigham Young University in Provo or the "S" for Snow College in Ephraim.

[4] On M-day (which typically takes place the last week of school), freshmen, sophomores, and juniors clear vegetation from around the M and whitewash it to keep it visible.

Each year during homecoming week, students from each class fill white paper bags with dirt and place a candle in each.

Previously letter-lighting took place by students collecting cans, filling them with used motor oil, and outlining their class letters on the mountainside up Manti Canyon over the old gravel pit.

The indefinite moving of the tradition to the fairgrounds in 2001 or 2002 was due to worries about fire and environmental damage from the oil.

[10][11] In the first few years that Manti High had a basketball team, it defeated nearly every opponent and placed third in the State Invitational Tournament.