In the late 1980s, the Federal Communications Commission (FCC) awarded a construction permit to build a new FM radio station in Orlando to the Urban Broadcasting Corporation.

Its creators sought to bring back a listening experience similar to early FM rock stations of the late 1960s and 1970s, focusing on music rather than contests and promotions.

Its library stretched from the mid-1960s to current releases, unlike many stations that focus on small slices of music from specific genres.

The station derives its call letters from WMMS in Cleveland; the founding programmer and chief engineer, Cary Pall, was a fan of WMMS, and secured the call sign to honor the legendary rock station, even though WMMO's format was not as rock-oriented.

Around 2015, WKGR's transmitter was moved about 20 miles south to Wellington, near West Palm Beach; because of this, WMMO was able to increase its power and antenna height slightly.

Infinity quickly spun off WHOO (now WTLN), WHTQ (now WOEX) and WMMO to Cox Radio, so the company could acquire WCKG in Chicago.

Recently, WMMO has moved its music in a direction to become the de facto Classic Rock station for Orlando.