It first signed on in 1925 and is primarily associated with the popularization of country music through its weekly Saturday night program the Grand Ole Opry, the longest-running radio program in history, begun as the WSM Barn Dance in 1925. WSM played a major role in the history of American music and radio by broadcasting country music's signature program over a huge area for decades.
The station traditionally played country music in the nighttime hours, when listeners from around the United States would tune in. Before the advent of television, the station broadcast long-form radio (both local and NBC network) programs in addition to music. After television became popular (thus laregely eliminating the audience for the old full-length radio programs of the past), WSM adopted an "MOR" (Middle of the Road) music format during the daytime hours, and continued to play country music at night. It was not until about 1979 that WSM adopted a 24-hour country music format, which it continues to program to this day.
Its unusual diamond-shaped antenna (called a Blaw-Knox Tower) is visible from Interstate 65 just south of Nashville (in Brentwood) and is one of the area's landmarks. At 808 feet, it is the tallest of eight such towers that remain in use in North America. As a tribute to the station's centrality in country music history, the diamond Blaw-Knox antenna design was incorporated into the new Country Music Hall of Fame and Museum's design in 2001. It was also part of the CONELRAD US National Emergency Plan in the event of a nuclear war, or another national catastrophe.
WSM's companion station, WSM-FM, was the first to broadcast on the FM band in the United States, beginning in the late 1940s, but has not been on the air continuously ever since nor always under the 'WSM' callsign (the current WSM-FM began in 1968, an acquisition from another broadcaster); hence other FM stations have a longer history of continuous operation.
Until 1981, the radio stations, an associated television station, and the Grand Ole Opry were owned by the former National Life and Accident Insurance Company and the call letters derived from the company's motto, "We Shield Millions". The television operation was sold to Gillett Broadcasting and changed callsign to WSMV; however, there was still a considerable overlap in the on-air personnel of the two operations in the years immediately following this change. The proceeds from this sale were used to finance the launch of The Nashville Network (now Spike TV). In 1983, the American General Corporation (now part of the American International Group) bought NL&AIC. American General, which had no desire to operate broadcasting outlets, soon decided to sell the NL&AIC entertainment assets, including Opryland Hotel, Opryland USA, The Grand Ole Opry, WSM-FM, and WSM to Gaylord Entertainment Company.
In recent years, the operations have been reorganized again. In 2003, WSM-FM and WWTN, sister stations to 650 WSM, were sold to Cumulus Media. Cumulus intended to purchase 650 WSM as well, but Gaylord decided to maintain ownership at the eleventh hour. Through a joint sales agreement, however, Gaylord pays Cumulus a fee to operate WSM's sales department and provide news updates for the station. Gaylord Entertainment continues to control WSM and operate all other departments, including programming, engineering, and promotions.
The Opry, WSM, and its hotel division are now Gaylord Entertainment's core holdings. A rumor circulated in the press in 2001, indicating that WSM might convert to a sports talk format, as many AM stations across the country have done in recent years. This prompted a serious outcry from country artists and local listeners alike, some of whom went so far as to protest outside the station's offices. The company eventually reaffirmed its commitment to retaining the country format, and it is now earning respectable ratings among the Nashville listening public.
Since October 2002, the station had been a choice on Sirius Satellite Radio, which carried a full-time simulcast of WSM's AM 650 signal, except during NASCAR races. In 2006, the Sirius channel programmed by WSM ceased carrying the AM simulcast. WSM still programmed the channel known as WSM Entertainment (Channel 111) as a separate satellite radio feed, and it carried the same classic country music format as the AM signal. WSM personalities voiced announcements on WSM Entertainment. Some programs on AM 650 were still carried on WSM Entertainment, such as the evening request program and the Grand Ole Opry. As of September 13, 2006, WSM programming is no longer carried on Sirius. About a year later, rival XM Satellite Radio announced the carriage of the Grand Ole Opry on Nashville! channel 11 beginning in October 2007, as well as the Eddie Stubbs Show on America channel 10 beginning in November 2007.
WSM currently operates out of the former Roy Acuff and Minnie Pearl museums adjacent to the Grand Ole Opry House. The studio itself is located within the Gaylord Opryland Hotel, and visitors to the hotel may look into the studio 24 hours a day, provided the curtains are open, which they usually are.