The track was built by the Allied Sports Association, formed by five World War II veterans who pooled resources to purchase approximately 55 acres of former farmland on the south side of Route 9 that had belonged to the DeBoer family. The founders — Roland and Leo Turgeon, Norman MacDonald, Joseph Henebry, and Richard Trum — were from the Framingham and Natick area. Construction cost was reported at $100,000. The first race was a 25-lap midget car event on Tuesday 5 August 1947, won by Joe Sostilio, a veteran dirt track driver and member of the Bay State Midget Racing Association. An estimated 9,255 people attended the opening night, with reports describing every grandstand filled to capacity. The facility featured a quarter-mile asphalt track encircling a central green lawn, surrounded by high wire fencing, floodlights, and public address amplifiers. Seating capacity was approximately 7,500.
Midget car racing was the foundation of the Westboro program. Midgets — cars with 300 to 400 horsepower engines in roughly 1,000-pound chassis — raced at the track exclusively through 1949, then on a monthly basis until 1957, returning to weekly events until 1969, and continuing monthly until the 1985 closure. As the venue matured through the 1950s, additional categories were introduced: sportsman and bomber classes grew into regular fixtures, and by the late 1960s the car pool had expanded to include modifieds based on contemporary muscle cars such as the Chevrolet Camaro and Ford Mustang. In the 1970s the modified division operated with four-cylinder engines capable of reaching 80 mph and lapping the quarter-mile in approximately 13 seconds. The racing season ran from April to September, with events on Friday and Saturday nights. Typical weekly crowds ranged from 1,500 to 3,000 fans, rising to 3,000–4,000 for regular events and as high as 10,000 for special occasions including demolition derbies.
Notable drivers who competed at the speedway included Geoff Bodine and Ron Bouchard in the mid-1970s. Bodine went on to a lengthy NASCAR Cup career; Bouchard, a Fitchburg native, won the 1981 NASCAR Winston Cup Rookie of the Year award. In 1982, the circuit hosted two events on the NASCAR North Tour — one in June and one in September — representing the track's peak involvement in nationally sanctioned competition. Track championship records show consistent competition across multiple categories through the early 1980s, with the Modified and Late Model standings among the most competitive divisions.
Among the regular faces in the modified class was driver Fats Caruso, who was a consistent points leader through the late 1950s and into the 1970s. Championship standings from 1955 through 1984 show a succession of regional New England competitors across sportsman, bomber, modified, late model, mini-modified, and super street stock categories.
Beyond racing, Westboro Speedway served as a multi-purpose entertainment venue. Rock concerts became a feature in the 1970s; Aerosmith played at the speedway on 18 August 1974 in what was described as the band's first outdoor headline concert, drawing a crowd of approximately 10,000. The Gregg Allman Band appeared in 1983. The facility also hosted demolition derbies — which regularly drew large crowds, with participants driving in reverse to protect their engines while colliding with other cars — as well as motorcycle enduros and motocross events in the infield, the annual Joie Chitwood Hell Driver Thrill Show, the Grotto Rodeo, wrestling matches, circuses, and seasonal flea markets in the parking lot.
Three fatalities occurred at the speedway during its operational history. On 25 May 1962, a spectator from Gardner, Massachusetts, was killed when a race car entered the crowd. On 19 June 1965, a driver from Schenectady, New York, was killed during a race. On 28 August 1965, a second driver from South Grafton, Massachusetts, was killed in a separate incident.
Attendance declined in the 1980s as the socioeconomic character of Westborough shifted from a blue-collar industrial community to a high-technology office corridor. Internal ownership changes, financial difficulties, and ultimately foreclosure accelerated the end. The final checkered flag fell on 14 September 1985. The property was sold to a developer and demolished in 1988. A strip mall, initially called Speedway Plaza, was built on the site and has continued to bear that name.
Despite its closure, the track retained a dedicated community of former participants and fans. Periodic reunion events have been organised, with former drivers displaying old race cars and signing autographs. A Facebook group dedicated to the speedway had accumulated more than 3,300 members as of the early 2020s. Two books have been written about the speedway's history, and records at the Westborough History Room document the facility's role in the region's mid-twentieth-century recreation culture.