The conference was formed in 2005 when most of these schools split off from the South Inter-Conference Association (SICA). The division resulted in a lawsuit claiming that schools that were majority white in population were abandoning the schools which were majority black. The lawsuit was eventually settled and paved the way for the conference to expand.
For 33 years prior to 2006, most of the public high schools in the south and southwest suburban Chicago area were a part of the South Inter-Conference Association (SICA) which by 2005 had reached a membership of 33 schools split into five divisions. The conference covered a large geographic area and sociological spectrum "from the Indiana border to Joliet, from impoverished Ford Heights to affluent Frankfort, from virtually all-black Hillcrest to almost all-white Lincoln-Way Central and from Joliet, enrollment 4,993, to 1,066- student Rich South" In 2004, the athletic directors voted 30–3, the principals' board of control voted 6–2, and the district superintendents voted 16–3 to approve a new conference realignment which was to take effect in 2006. The realignment had been pushed because of long travel times and a reduction of sports offerings at some schools. The realignment split the association into three roughly equal and geographically contiguous conferences, one of which, the southeast, contained most of the predominantly African–American schools (compared to one school in the remaining two conferences). It was from these schools that a majority of the votes against the realignment had come. Leaders from these schools demanded an investigation from the Office of the Illinois Attorney General, and petitioned the Illinois State Board of Education to investigate as to whether this action violated rules on equity.
In March 2005, ten schools announced that they were unilaterally leaving SICA to form a new conference, the Southwest Suburban Conference. These ten schools collectively were among the largest in student population. Shortly after the announcement, a board member from Lincoln-Way Community High School District, a district representing two of the schools leaving to form a new conference, was forced to resign after racially insensitive statements were left on a reporter's voice mail.
Shortly after this, eleven more schools split off to form the South Suburban Conference.
In April 2006, a federal civil rights lawsuit was filed against the schools which had left claiming that "(an) apartheid-like realignment used public funds to regress to separate but equal". The suit was settled out of court with the three schools of Thornton Township High Schools District 205 joining the Southwest Suburban Conference, and the two schools of Thornton Fractional Township High School District 215 joining the South Suburban Conference. The remaining six teams would remain known as SICA.