First recorded by Seafood Mama (1980).
Hit version by Quarterflash (US #3/ROCK #1/UK #49/AUS #6/NZ #12 1982).
From the wiki: “‘Harden My Heart’ was originally released as a single in early 1980 by Seafood Mama, Quarterflash’s predecessor band. That recording featured a more sparse instrumental arrangement but also a more dramatic vocal arrangement than the later hit version. The original single was a regional success on radio stations in the Pacific Northwest.
“After changing the group name, Quarterflash released their self-titled debut album in 1981 on which was the new version of ‘Harden My Heart’. This version, produced by John Boylan, was released as the album’s first single, in September 1981, which peaked in the Billboard Top-5 and topped the Mainstream Rock chart in early 1982.”