Defenders of the Faith was recorded at Ibiza Sound Studios, Ibiza, Spain and mixed from September to November 1983 at DB Recording Studios and Bayshore Recording Studios in Coconut Grove, Miami, Florida. The LP and cassette tape were released on 4 January 1984, and the album appeared on CD in July. A remastered CD was released in May 2001. Simultaneously with the album's release, the band kicked off their tour in Europe, with the bulk of concerts taking place in North America during the spring and summer.
Stylistically, Defenders of the Faith did not greatly depart from its predecessor and contained the same mix of short, up-tempo metal anthems with stadium shoutalong choruses, although progressive elements returned on some tracks such as "The Sentinel".
The album was an immediate success, only going one spot below Screaming for Vengeance on the US Billboard 100 Albums Chart, and would mark the apex of Judas Priest's commercial success. Some critics nonetheless objected to the lack of a standout single comparable to "Breaking the Law" or "You've Got Another Thing Comin', and the album's general similarity to Screaming for Vengeance.
The 30th-anniversary release of the album (released in March 2015) came with a double CD of a live show recorded on 5 May 1984 at the Long Beach Arena in Long Beach, California on their Defenders of the Faith Tour and was originally recorded for a radio broadcast.
The cover art by Doug Johnson (who also designed the Hellion in Screaming for Vengeance) depicts the Metallian, a ram-horned, tiger-like land assault creature with Gatling guns and tank tracks conceptualized by the band. The back cover contains a message:
"Rising from darkness where Hell hath no mercy and the screams for vengeance echo on forever. Only those who keep the faith shall escape the wrath of the Metallian... Master of all metal."
"Eat Me Alive" was listed at number 3 on the Parents Music Resource Center's "Filthy Fifteen", a list of 15 songs the organization found most objectionable. PMRC co-founder Tipper Gore stated the song was about oral sex at gunpoint. In response to the allegations, Priest recorded the song "Parental Guidance" on the follow-up album Turbo.
On the tour for this album, the band played every song live, with the exception of "Eat Me Alive". On the tour for the Nostradamus album in 2008, they played many songs which had never been played live before, one of them being "Eat Me Alive". This made Defenders of the Faith the second Judas Priest album from which every song had been played live (the first being Rocka Rolla).