Southern High School Magnet Career Academy (MCA) was built in 1951, and the first graduating class was in 1952. All students had transferred from the recently closed Okolona High School, which became Okolona Elementary School.

Unlike in many high schools, students eventually choose a "major," including business technology, telecommunications, machine tool and die technology, and transportation technology.

Starting in the 2011–12 school year, the "Freshman Academy", which is devoted to help freshmen adjust to high school, was opened. Freshmen do not have their own lunch. However, they have taken a part of the 3rd and 2nd floor to be used as the Freshman Academy area.

Starting in the 2011–2012 school year, with the new principal came a change known as "Southern 3.0 Upgrade", in which the school has become more involved and more rigorous with learning.