The road is named after Ernest W. Barrett, the first chairman of the Cobb County Board of Commissioners in the 1960s, after home rule was enacted under a Georgia State Constitution amendment.

During the 1980s, dramatically-increased land development, most notably the extension of I-75 in 1977 (which cut Roberts Road in half south of Barrett Parkway), the construction of I-575 in 1980, and the completion of the major regional Town Center at Cobb shopping mall in 1986, strained the road to capacity, and was subsequently widened to six lanes (three in each direction, plus turn lanes) with a median by the Cobb County Department of Transportation.

Today, Barrett Parkway is densely packed east of Old 41 Highway with major shopping centers and restaurants.

Stilesboro Road east from Barrett Parkway, and Old US 41 south from it, meet at the historic Kennesaw Mountain National Battlefield Park, next to the visitor center.

Villa Rica Road, which was realigned westward at SR 120 to meet Ridgeway to complete the loop, also had its parkway-widened portion renamed.

After a small minority of residents approved a sales tax increase in a little-known referendum in September 2005, one of the projects to be funded is making it a six-lane highway from US 41 to SR 120.

[3] This would give it as many lanes as some much busier roads in the county, and would contradict promises made to residents before initial 1990s construction.

As of 2012[update], the South Barrett Reliever is partly completed, extending the four-lane divided Barrett Lakes Boulevard southwestward down formerly two-lane Greers Chapel Road to Cobb Parkway (where it continues as Ridenour Road, renamed from its historic name for a new development of expensive homes adjacent to it).

In longer-range plans, a new roadway will be constructed from this point eastward to Bells Ferry Road, including a second bridge across I-575.

To complete this, traffic on I-75 was detoured in 2011 onto temporary roadways in the very wide median where trees used to be, and much of the dirt removed to construct new bridges, a project done by the Georgia Department of Transportation (GDOT).

This new alternate route connects KSU with its new soccer stadium, and would also be a bus rapid transit station and an interchange with the reversible express lanes on the proposed Northwest Corridor HOV/BRT.

The ramps would also likely be expensive due to the large amount of rock in the area, as is seen on both freeways where they cross the ridge immediately north of where they split.

[4] In southwest Cobb, at Powder Springs Road (original SR 5), Barrett Parkway changes name to East–West Connector, and bends southeast.

From here, it then travels east to SR 280 (South Cobb Drive), through the Concord Covered Bridge Historic District.

This area is also notable for the deep, gorge-like cuts into the rock, like between the Silver Comet Trail and Concord Road overpasses.

It is mostly residential and entirely divided, with pin oak, holly, and other smaller trees in the medians, and left-turn lanes.