The song is in Eb major. It has a power ballad style and incorporates many of the characteristics of rock ballads, including driving electric guitar riffs by Joe Perry and Brad Whitford, pianos and violin sounds (from a keyboard), an emotional delivery of lyrics by Steven Tyler, a strong rhythm by bassist Tom Hamilton, and well-placed steady drum beats by Joey Kramer.
The music video for "Angel" focuses primarily on a character played by Steven Tyler who is hypnotized by an intangible angel, presumably his ex-lover. There are also scenes of him playing the piano. The other band members can be seen playing their instruments on city streets, and there is a notable guitar solo by Joe Perry on a rural highway. The video was directed by Marty Callner.
Steven Tyler has publicly spoken against the song on numerous occasions. He was quoted saying on a radio interview in 1990 "The song was beautiful. It made me cry. But I heard it so damn much it drove me crazy! It became overplayed and at this point I'm so sick of it I never want to hear that song again". Since the Pump Tour in 1989-1990 the song has become somewhat of a rarity. A live performance appears on the live album A Little South of Sanity, released in 1998.