Central to the new design of New Haven City Hall is the retention of the facade of the original building as both the symbolic and functional main entrance to a new municipal complex. The new, six-story office annex extends the façade, an abstract version of the original City Hall, north, strengthening it in relation to the high-rise buildings on either side.

Designed by noted New Haven architect, Henry Austin and completed in 1861, New Haven's City Hall is an exuberant, early example of High Victorian Gothic architecture. Dominating the historic New Haven Green, it was listed on the National Register of Historic Places in 1975.

Combining preservation, restoration and new construction, its renewal is the culmination of a decades-long effort by citizens to preserve the building and incorporate it meaningfully into the new government center development.

The mayor's offices were returned to their original location overlooking the Green. The central four-story stair hall, which had been demolished, was reconstructed along with its original cast-iron staircase, skylight and vaulted ceiling.

One of the most important organizing elements in the restoration and addition to City Hall is the new colonnade, the largest public space in the building, providing access to City agencies, the Aldermanic Chamber and the Hall of Records. The City agencies visited most often by the public are located on the colonnade's first floor. The Aldermanic Chamber, the heart of the municipal process, is located on the balcony level.