In the 1970s round of redistricting, the Louisiana State Legislature (in complying with the Voting Rights Act of 1965, particularly the opportunity of racial minorities to elect a representative of their choosing) redrew the neighboring 2nd District, which previously contained most of the western parts of New Orleans as well as the Westbank suburbs (on the west side of the Mississippi River, hence the term) in neighboring Jefferson Parish, into a majority African American district.

Accordingly, the new 1st gave Republican President Richard Nixon over 70 percent of the vote in his 1972 reelection, though it did give a narrow majority to Democrat Jimmy Carter in 1976.

However, Tonry would quickly become the subject of a federal corruption investigation, including allegations of ballot stuffing in St. Bernard Parish as well as illegal campaign contributions, eventually pleading guilty, serving a six-month prison sentence and resigning from Congress after only four months in May 1977.

In particular, several central and eastern portions of New Orleans that were becoming increasingly African American and Democratic (including in particular New Orleans East, which would be adversely affected by the 1980s oil glut and the ensuing demographic changes that affected property values and crime rates there) were moved to the itself majority African American 2nd District.

In exchange, the 1st added several heavily Republican areas of Jefferson Parish from the 3rd District (including the East Bank suburbs of Metairie and Kenner, as well as most of the Westbank suburbs including Terrytown, Estelle and Avondale) that not unlike St. Tammany Parish experienced a similar trend towards the GOP after World War II.

As of the 2020s round of redistricting, as well as a subsequent mid-decade redistricting that resulted in a second majority-African American district being created before the 2024 elections, the district remains about equally divided on both sides of Lake Pontchartrain, with the northern portion extending from all of St. Tammany Parish to southern portions of Tangipahoa, Livingston and Ascension parishes (the latter two located in the Baton Rouge metropolitan area) including as far west as Sorrento, and the southern portion split between Scalise's political base in the East Bank suburbs west of New Orleans on one end and the southeastern corner of the state across most of St. Bernard, Plaquemines and Lafourche parishes.