Route 128 had its humble beginnings in the early 1920s (latest 1926) as a string of local roads from Route 138 (Blue Hill Avenue) in Milton to Salem Center. The route passed through Readville, Dedham Center, Needham Center, Newton Highlands, Newton Center, Waltham Center, Lexington Center, Woburn Center, Stoneham Center, Wakefield Center, South Lynnfield, and Peabody Center. (msg me if you want the complete routing for this or any other alignments)
By 1929 the route had been extended to Quincy Center from its Milton end. In 1931 and 1932, the first section of the Circumferential Highway was built, from Route 9 in Wellesley to the Blue Hills Reservation, where traffic was dumped onto existing local roads. The original Circumferential Highway was a two to three lane (total) roadway with limited access. Interchanges were built at Route 1 in Dedham, Route 135 (West Street) in Dedham, and Highland Avenue in Needham; other intersections were at-grade. Route 128 was assigned to the Circumferential Highway south of Highland Avenue in Needham (north of there was temporarily unnumbered), and old Route 128 east of Needham Center became Route 135. At the same time, Route 128 was extended to Nantasket (part of (Hull)), via Braintree Center, South Weymouth, and Hingham.
Also at some time in the 1930s, Route 128 was extended north to Gloucester Center via Beverly Center and Manchester Center. This route was also Route 127 at the time, and still is.
In the late 1930s and 1940s, improvements started in stages north of Boston, and old Route 128 became Route 128A for a short period of time before reverting to unnumbered status. These were generally four lane surface roads but included some interchanges. Specifically, interchanges were placed at:
Route 129 (Lowell Street) (Wakefield), where the highway began for several years
Main Street (Wakefield)
Main Street (Lynnfield)
Salem Street (Wakefield)
Walnut Street (Lynnfield)
Route 1 (Lynnfield)
Lowell Street (Peabody)
Route 114 (Andover Street) (Peabody)
Route 35 (High Street) (Danvers)
Route 62 (Elliott Street) (Danvers)
Route 1A (McKay Street) (Beverly)
Brimbal Avenue (Beverly)
Route 22 (Essex Street) (Beverly), where the highway ended for several years
The road may have been signed as Temporary Route 129 at first; this is seen on a 1964 map.
In the late 1940s, Massachusetts began constructing new highways to full freeway standards. The rest of the route from Route 9 in Wellesley to Route 127 (Washington Street) was thus built as a full freeway by the mid-1950s. In addition, the section south of Route 9, until the Blue Hills Reservation, was hugely upgraded in the mid-1950s. Several 1930s bridges were retained, and some old sections remain (Reservoir Street, Greendale Avenue, Blue Hill Drive). In the mid to late 1950s, the rest of the freeway was completed to the Braintree Split, as well as Route 3 south of the split, which was cosigned with Route 128 to the Derby Street interchange. The late 1940s-early 1950s section north of Boston was mainly upgraded in the late 1950s and early 1960s, although some non-freeway sections remained in Peabody and Beverly. Route 128 was also extended for the last little bit in Gloucester, which is still a surface road with rotaries and traffic lights to this day.
Between 1961 and 1969, Route 128 was cut back in the south to the Southeast Expressway (Route 3) at the Braintree split. The surface section to Nantasket became Route 228.
In the late 1980s, the at-grade section in Peabody was finally upgraded, with the completion of Interstate 95 north of Route 128; the old road is now Jubilee Drive. The at-grade section in Beverly remains, but the median has been closed.
In 1997, MassHighway removed Route 128 from the section of road south/east of the Interstate 95 interchange in Canton. They tried to do it all the way to the Peabody split, but local opposition overruled.
Nowadays, Route 128 carries Interstate 95 from Canton to Peabody, due to the cancellation of the downtown expressway system. Standard signage omits Route 128 from guide signs and uses a separate trailblazer assembly for Route 128. North of the Peabody split, Route 128 is on its own to Gloucester, as it has always been.