The band premiered "Last of the American Girls" during a secret show at the Fox Oakland Theatre on April 14, 2009, alongside other songs which would appear on 21st Century Breakdown.

[6] The song advances the story of 21st Century Breakdown through expanding on the idealistic and politically-driven personality of the character Gloria.

[12] The video shows a bored Gloria in a desert landscape strewn with furniture performing mundane activities like watching television and washing dishes while being followed by a pair of dancing blond twins.

[13] Towards the end, Gloria causes a shooting target to burst and a car to explode by "firing" a finger gun.

It is one of the few songs in the musical to originate from 21st Century Breakdown, as opposed to being from the album American Idiot itself.