The station's studios and offices are located in Bala Cynwyd and the transmitter is atop One Liberty Place at (39°57′9.4″N 75°10′3.6″W / 39.952611°N 75.167667°W / 39.952611; -75.167667) in Center City Philadelphia.

[5] In the 1950s and 1960s, WIP-FM carried a full service format of middle of the road (MOR) music, news, sports and talk.

Beginning in 1968, WMMR began adopting a progressive rock format, similar to that of several Metromedia-owned stations including WNEW-FM in New York City.

WNEW-FM and WMMR had a close relationship, ran similar promotions, and sometimes featured each other's disc jockeys on the air.

WMMS in Cleveland, KMET in Los Angeles, and KSAN in San Francisco were also part of the Metromedia chain and also helped pioneer the progressive rock format in the 1960s.

[8] Michael Cuscuna from the University of Pennsylvania's WXPN replaced Herman in 1970, but was quickly hired away by WABC-FM (now WPLJ) in New York City.

One of WMMR's most influential disc jockeys during the 1970s was Ed Sciaky, who was known for playing and boosting the careers of new artists such as Billy Joel and Yes.

WMMR alumni include David Dye, host of the World Cafe on WXPN and syndicated on many NPR stations.

One-time WMMR midday DJ Dick Hungate later switched to WYSP, pioneering the classic rock format in Philadelphia.

[10] On October 26, 1987, Metropolitan Broadcasting applied for a construction permit to change the transmitter location to "Building Rooftop 1650 Market St., Philadelphia, PA" (the address of One Liberty Place) and increase the station's HAAT to 271 meters (889 ft).

[12] Group W Radio modified the construction permit on February 12, 1992, by decreasing the HAAT to 252 meters (827 ft) and changing the ERP to 18,000 watts.

[15] In May 2005, the station began airing the Preston & Steve show in morning drive, which was previously heard on WPLY.

In early 2006, WMMR launched its digital HD2 subchannel with the "WMMaRchives" format, airing the station's archive of live and studio performances.

This run would end in October 2022, when owners Beasley Media made major cuts to the staff of WMMR and other stations, resulting in the elimination of the live overnight block.

[20][21] In 2007, WMMR was nominated for the Radio & Records magazine award for "Active Rock Station of the Year" in a top 25 market.

Other nominees included WIYY in Baltimore, WAAF in Boston, KBPI in Denver, WRIF in Detroit, and KISW in Seattle.