Historically, the station is perhaps best known by its former WHDH call letters, under which it operated from its establishment in 1929 until 1994; it then became the second home to WEEI following an intellectual property purchase.

WHDH was able to increase power to 5,000 watts and go full-time, but not without protests from KOA, one of the dominant class A clear channel stations on 850 AM.

[5] In 1946, shortly after World War II, the Boston Herald-Traveler newspaper purchased WHDH, by this time again an independent station.

While the two stations for the most part programmed different kinds of music, both had very talented air personalities who were "household names" in the Boston area.

Perhaps the station's best-known on-air personalities outside of Boston were the comedy team of Bob and Ray, who did a comedy-and-records show at WHDH before they departed for national fame in New York City.

The station employed a popular MOR (what today would be called "adult standards") music format, which would also include soft rock songs by the end of the 1960s.

For 30 consecutive years, from 1946 to 1975, WHDH was the flagship station of the Boston Red Sox, featuring play-by-play announcers such as Jim Britt, Ford C. Frick Award-winning Curt Gowdy, Ken Coleman, and Ned Martin.

It was an afternoon telephone sports talk hosted by Leo Egan which ended after the station was sold to John Blair Broadcasting.

In addition, the original WHDH-TV (channel 5), which took to the air November 26, 1957,[4] was the flagship station of the Red Sox television network from 1958 to 1971.

[8] WHDH then elected to not renew its contract with the Red Sox upon its expiration following the 1975 season, citing financial losses;[9] the broadcasts moved to WMEX starting with the 1975 postseason.

Veteran disk jockeys were replaced by personalities with a top 40 background, such as former WRKO personality Tom Kennedy (the DJ, not the game-show host), Bob Raleigh from WPGC in Washington (owned by Richmond Bros., owners of WMEX), Sean Casey, who was formerly with WOR-FM in New York and Bill Silver, the well-known voice of per inquiry advertisements who put the phrase "but wait there's more" into the national lexicon.

On August 7, 1989, WHDH was sold to local businessman David G. Mugar, whose New England Television Corporation (NETV) owned CBS affiliate WNEV-TV (channel 7).

Mugar was hoping to bring back a main competitor to WBZ radio and television, with a renewed emphasis on news and straight talk format with some political programming.

[4] However, by 1992, NETV was in trouble due to increasing debt incurred by the channel 7 acquisition as well as declining advertising revenues, leading to speculation of a sale of WHDH radio;[16] on December 1, the station was sold to Atlantic Radio, putting it under the same ownership as rival talk station WRKO.

[25] ARS concurrently moved the Rush Limbaugh and Howie Carr shows, in addition to the "Skyway Patrol" traffic report brand, from WHDH to WRKO.

[25] WHDH's final broadcast, on August 28, 1994, concluded at midnight with "Taps" and the sound of a flushing toilet; these were played by a disgruntled board operator who was laid off in the transition, and subsequently led to a formal apology from ARS.

Due to conflicts with BC basketball, Boston Bruins broadcasts, which WEEI had carried on 590 AM, remained on that frequency even after the launch of WBNW;[25] the team had already announced its move to WBZ effective with the 1995–96 season.

[29] ARS also moved Red Sox broadcasts to WEEI from WRKO starting in 1995, marking their return to the 850 kHz frequency.

[39] As the combined company would have controlled 59 percent of advertising revenues in the Boston market, as well as three of the top five radio stations, in April 1998 the Department of Justice ordered CBS to divest WEEI, WRKO, WAAF (now WKVB), and WEGQ (now WEEI-FM), as well as KSD and KLOU in St. Louis and WOCT in Baltimore, as a condition of its approval of the merger.

[40] In August 1998, Entercom announced plans to acquire the four Boston-area stations, along with WWTM (now WVEI), from CBS for $140 million.

The exception is for Red Sox and Celtics games, as these are streamed only through the team and league websites as part of subscription packages.

[48] The ban came to an end on August 4, 2009, when Bob Ryan appeared on The Big Show, with host Glenn Ordway stating that "we have all come to our senses".

[49] In September 2009, The Boston Globe reported that ESPN Radio was in negotiations to clear some of its night and weekend programming on WEEI, with speculation suggesting that WEEI could subsequently move to one of Entercom's properties on the FM dial (such as the 93.7 FM facility then occupied by WMKK), with the AM 850 signal switching to ESPN Radio.

[51] As late as December 2010, station management continued to deny occasional reports of a move of WEEI's programming to WMKK.

In October 2021, WEEI dropped ESPN Radio in favor of sports betting programming from the Audacy-owned BetQL Network.