The set includes several rare and unreleased songs alongside more obscure album tracks that showcase Petty's songwriting.

[3] Petty's daughter Adria made a promotional music video for the track "Keep a Little Soul" using home movies.

[1] Writing for Uproxx, Steven Hyden called the compilation "especially refreshing" for focusing on alternative recordings and more obscure songs from Petty's catalogue, summing it up as, "a surprisingly good introduction for neophytes, no matter the dearth of hits".

[9] Stephen Thomas Erlewine of AllMusic gave the compilation 4.5 out of five stars, writing, "this box winds up as a fitting tribute to a rocker whose touch was so casual, he could be easy to take for granted, but when his work is looked at as a whole, he seems like a giant".

The deluxe version of An American Treasure features 60 songs (plus one radio promo spot and two concert dialogue snippets, for a total of 63 tracks) spread across four CDs.