On Andrew Jackson's orders, the Chalmette plantation was completely destroyed during the battle to prevent the British from using it for cover.

[8] On August 29, 2005, a 25-foot (7.6 m) storm surge from Hurricane Katrina overflowed through the Mississippi River–Gulf Outlet Canal (commonly known as MRGO) — a commercial channel dug by the United States Army Corps of Engineers in the 1960s — and flooded most of the town, with waters as high as 14 to 15 feet (4.9 m) in some places.

Despite findings published by the U.S. EPA, the toxic chemicals in the water from local oil refineries have been postulated to be an ongoing health hazard by several civilian ecological groups.

[10] The parish administrative headquarters served as the site for a Federal Emergency Management Agency (FEMA) trailer park for numerous civil servants who were laboring in the rebuilding effort.

Deputies working for the St. Bernard Parish Sheriff stated in early December 2005 that the oil tank floated in the flood.

By late November, the Murphy facility was functional, as was a small cluster of businesses around the intersection of Paris Road and St. Bernard Highway, on the least damaged River side of Chalmette.

The devastated residential areas farther away from the River were open during daylight hours, for residents to salvage belongings from their damaged homes.

Other organizations, such as the St. Bernard Project, have also participated in the rebuilding of Chalmette, from distributing supplies, to clearing debris, to repairing damaged houses.

In February 2006, the krewe of the Knights of Nemesis held a parade, past many buildings still in ruins, along the streets of Chalmette.

As of early 2008, many businesses have returned to the area, schools have reopened, although the population remains significantly below pre-Katrina levels.

The Roman Catholic Archdiocese of New Orleans has consolidated all local schools into one, on the Our Lady of Prompt Succor campus.