The Cape-Atlantic League was formed in the Fall of 1949 by six schools – Cape May, Egg Harbor City, Hammonton, Middle Township, Ocean City, and Wildwood. In 1960, Egg Harbor City closed its doors and Oakcrest opened. The next year, 1961-62, newly opened Mainland Regional joined the league, along with Pleasantville, increasing the number of schools to eight.

The CAL remained at eight schools until 1968-69 when Sacred Heart and Wildwood Catholic became the first non-public schools to join. That increased the number of schools to 10. Mainland and Oakcrest left the league in 1969-70, dropping the number back to eight. It increased to 10 again in 1973-74 with the addition of Buena and St. Joseph of Hammonton.

Those were the 10 schools in the league in 1982-83 when the Cape-Atlantic League merged with the Southern Division of the South Jersey Conference. That brought Mainland and Oakcrest back into the league along with Atlantic City, Holy Spirit, Absegami, Millville, Vineland, Bridgeton, and Cumberland. St. Augustine Prep, previously an independent school, also joined. Two conferences – the American, for schools with larger enrollments, and the smaller National – were created, generally along the same lines as the two old leagues. Each conference has been broken up into two divisions in some sports, also determined by enrollment.

Egg Harbor Township joined in 1983-84 and, in subsequent years, Cape May Tech (1996-97) and Our Lady of Mercy (1998-99) came aboard. As the CAL entered a new century, Cumberland left to join the Tri-County Conference in 2000-01, and Wildwood, after 53 continuous years as a member, also left in 2002-03 to join the Tri-County Conference. In 2010-11 a new high school – Cedar Creek of Egg Harbor City – joined the league and in 2012-13 another school the Atlantic County Institute of Technology in Mays Landing joined as well after they initiated their varsity sports program. In the spring of 2013, the league lost one of its’ initial non-public school members when Sacred Heart of Vineland closed at the end of the school year.  In the summer of 2014 Hammonton, one of the original members from the group of six in 1949, left the CAL after being a continuous member of the league for 65 years to join the tri-county conference. Hammonton returned to the CAL in the summer of 2020.

Currently, the Cape-Atlantic League comprises 22 schools from Atlantic, Cape May, Cumberland, and Gloucester counties. It has developed into one of the most successful leagues in the State of New Jersey.