Although considered a separate station in its own right, WSHM-LD is actually operated as a semi-satellite of WFSB (channel 3) in Hartford–New Haven, Connecticut.

In 2003, the Meredith Corporation (having acquired WFSB in June 1997) purchased W67DF in order to set up a separate operation in the Pioneer Valley.

Reasons for such a launch ranged from local advertising opportunities, to being able to assert the Pioneer Valley as a secondary New England Patriots market as the team started its two-decade Brady–Belichick era.

In November of that year, the station joined CBS and adopted the call sign WSHM-LP after officially upgrading to low-power status.

On June 27, the master control and internal operations of WSHM and WFSB moved to a newly constructed facility (south of Hartford) in Rocky Hill.

Meredith eventually removed WFSB from those systems due to corporate and network affiliation agreements requiring only WSHM-LD's ratings to account for CBS in the Springfield market.

However, the deal is permissible under FCC rules which allow common ownership of full-power and low-power television stations (the respective class designations of WGGB and WSHM) in all markets.

[7] As a result, WSHM-LD became a sister station to fellow CBS affiliates WCAX-TV to the north in Burlington, Vermont, and WWNY-TV in Watertown, New York.

Initially after entering the news race in the Pioneer Valley, it struggled to make a dent in the ratings of longtime market leader NBC affiliate WWLP and established runner up ABC outlet WGGB.

Eventually, this station grew substantially across the board during the May 2009 sweeps period to within decimal points of WGGB in several key demographics.

Compared with the area's two other commercial television stations, WSHM tended to have a flashier format in its newscasts featuring more fast-paced coverage.

[12] In September 2010, WSHM debuted an updated local news format that contained the top stories of the day and a full weather segment shown in the first five minutes of all newscasts before a commercial break.

Known as "Early Warning Pinpoint Doppler", this is based on top of a terminal building at Bradley International Airport in Windsor Locks, Connecticut.

The combined news operation is based out of WGGB's facilities on Liberty Street; this led to the closure of WSHM's Monarch Place studios following the April 20, 2015, newscasts.

Generally, the latter would be preempted by CBS Sports programming most weekend early evenings, with WGGB airing news at those times outside of the college football season.

From the launch of its digital signal, it numbered as a subchannel of WFSB, specifically 3.5 and later, 3.7, to avert confusion with its Hartford sister station under Meredith ownership.

An application filed with the FCC calling for WSHM to launch its own low-powered digital station on channel 49 was dismissed in June 2006.

[17] WFSB's digital signal continues to have good reception into southern areas of the Pioneer Valley, thus allowing access to two CBS affiliates.