The Southwestern Conference was formed in 1937 as a three-team league with Berea, Oberlin, and Rocky River as members. Five teams were added in the decade of the 1940’s as the league added new members on four occasions. Fairview was admitted in 1940, Clearview in 1945, Wellington in 1946, and Amherst and Medina in 1947. The stability of the league was short lived as Berea exited in 1950 to join the Greater Cleveland Conference. In 1954, Amherst, Clearview, and Wellington left to join the newly formed Lakeland Conference. Bay Village, North Olmsted, Olmsted Falls and Westlake then joined Fairview, Medina, Oberlin and Rocky River to form the eight-team league that would remain intact for ten years.

In 1964, Oberlin departed and Avon Lake was admitted. The SWC then remained unchanged for twenty-two years. In 1986, Medina left for the Pioneer Conference and Amherst returned to the league after a thirty-two year absence. After nineteen years of no change, in 2005 Rocky River High School, Fairview High School and Bay Village High School departed the conference to form a new West Shore Conference. Berea High School returned to the Southwestern Conference in 2005 along with new members, Midpark High School and Brecksville-Broadview Heights High School.

Changes to the conference make-up occurred once again in 2013 when Midpark High School and Berea High School merged in to the new Berea-Midpark High School thus reducing conference membership to 7 schools. Avon, Lakewood, Midview and North Ridgeville joined while Brecksville-Broadview Heights left in the fall of 2015 to bring the membership to an all-time high of 10 schools.

Lakewood departed in 2020-21 and North Olmsted and Westlake followed in 2021-22. Elyria High School joined that same year, which enabled the SWC to return to an 8-team league.

Today the Southwestern Conference provides athletic competition for young men and women in 25 sports. The SWC also provides academic competition, a college fair and an annual instrumental and vocal music program to round out a varied and sufficient program of opportunities for the students of the member schools.