The original, open-air mall was built by Sol Atlas and opened in 1960, anchored by a W. & J. Sloane furniture store and a Stop & Shop supermarket at opposite ends. In 1962, the sixth branch of the Alexander's department store chain opened. Following an early fire at the west end of the mall, a Caldor discount store was built as the new anchor.
In 1981, the mall was enclosed. The mall underwent a renovation in 1990 which added the Skyview Cafe food court, and lost anchor Alexander's. On August 7, 1991, JCPenney opened in the former Alexander's space. G. Fox was added in 1991 and was rebranded as Filene's in 1993. Caldor closed on May 15, 1999 and was later demolished. Stop & Shop relocated to a freestanding store sometime in the late 1990s and was demolished for Sears which opened on April 1, 2000.
A $118 million 480,000-square-foot (45,000 m2) expansion project took place in 2005–06, adding:
an additional level of parking
a 75,000-square-foot (7,000 m2) third floor to Filene's which was later rebranded as Macy's in 2006.
a large extension to the building with a 55,000-square-foot (5,100 m2) movie theater (Connecticut Post 14, replacing the Milford Fourplex, previously located in an adjacent building. Was Cinema De Lux, later a Rave Cinemas, now a Cinemark), a new food court, and two more anchors, Dick's Sporting Goods and Target on the site of the former Caldor.
In December 2015, Westfield sold Connecticut Post in a $1.1 billon deal involving 5 malls.
On March 17, 2017, it was announced that JCPenney would be closing as part of a plan close 138 stores nationwide. The store closed on July 31, 2017. On January 11, 2018, it was announced that Boscov's would be opening in the former JCPenney space on October 6, 2018.
On October 15, 2018, it was announced that Sears would also be closing as part of a plan to close 142 stores nationwide. The store closed in January 2019. It is unknown what will replace that space.