[1][2] He co-wrote "Rock in a Hard Place" with Steven Tyler, and has performed or recorded with Rod Stewart, Billy Squier, Meat Loaf, Stevie Nicks, Robert Fleischman, Rough Cutt, Renegade, Flame and others.
Returning to session work following the breakup of Flame, Crespo attracted the attention of Aerosmith's management following the departure of Joe Perry from the band in 1979.
Contributing a guitar solo to the song "Three Mile Smile" for the already recorded Night in the Ruts album, Crespo commenced touring with the band soon after joining.
The tour was hampered by the increasingly erratic state of the band's singer, Steven Tyler, at this stage heavily beset by drug addiction and suffering several on-stage collapses.
Xavier Russell said of it in Sounds: "As soon as the needle hit the wax, it melted and the speaker covers blew across the living room floor.
Crespo joined bassist Danny Sheridan and Bonnie Bramlett in their new band Bandaloo Doctors from 1987 to 1992 and returned to session work as well as touring and recording with Billy Squier for several years.
[4] Crespo performed with the HitMen All Stars featuring former members of Boston, Dire Straits, Journey, Fleetwood Mac & Night Ranger.