WCOP-FM went through a number of format and callsign changes, including beautiful music in the late 1960s until 1973, oldies (as "Total Gold 101, WCOP-FM") from 1973 to 1974, country from 1974 to October 1976, "progressive country" (as WTTK, "TK101") from October 1976 to December 1978,[3] beautiful music (as WHUE-FM) from January 1979 to January 1985,[4] and top 40 (as WKKT, "The Cat") for a few months, beginning in February 1985.

[7] WZLX is considered one of the classic rock format's earliest success stories as reflected by the station's 19th to 2nd place climb in the Adults 25-54 demographic in its first ratings period.

A series of ownership changes made WZLX a part of Cook Inlet Radio Partners, then Infinity Broadcasting in late 1992.

[8] In 2005, WZLX, along with sister stations WBMX and WODS, were rumored to flip to CBS Radio's ever-expanding "Jack FM" format.

On February 2, 2017, CBS Radio announced it would merge with Entercom (which locally owned WEEI, WEEI-FM, WKAF, WRKO and WAAF).

[9] On October 10, CBS Radio announced that as part of the process of obtaining regulatory approval of the merger, WZLX would be one of sixteen stations that would be divested by Entercom, along with sister stations WBZ and WBZ-FM, as well as WRKO and WKAF (WBMX, WODS, WEEI AM and FM, and WAAF would be retained by Entercom, while WBZ-FM was traded to Beasley Broadcast Group in exchange for WMJX).

To meet ownership limits set by the FCC, iHeart placed WKOX into the Ocean Stations Trust in preparation for a sale to a permanent buyer.

With the coming of Howard Stern to WBCN in the early 1990s, the Boston legend Charles Laquidara and his show, The Big Mattress, took up residence at WZLX.

[16] In addition, some Bruins games conflicting with WBZ-FM's New England Patriots broadcasts aired on WZLX starting in 2011 (previously, WBZ served this function).

[17] WZLX previously aired a freeform rock format on its HD3 subchannel called "WBCN" which continued the name of the former Boston AOR station.