Singer was born Eric Doyle Mensinger in Cleveland, Ohio. He grew up in Euclid, Ohio. His father, Johnny Mensinger, was of Jewish German descent and was a local big band leader who played around the area as well as on cruise ships from the States to Europe and back. Young Eric began playing drums from an early age, and was inspired by bands such as Humble Pie, The Who, Led Zeppelin, Black Sabbath, The Beatles and Queen and drummers such as John Bonham, Keith Moon, Cozy Powell, Roger Taylor, Bill Ward, and Buddy Rich.
Eric worked at King Musical instruments before becoming a professional drummer.
Singer's first professional drumming job was in the Cleveland band Beau Coup. He then became Lita Ford's touring drummer in 1984. In 1985 he joined Black Sabbath, replacing original drummer Bill Ward (actually Vinnie Appice replaced Bill Ward and played on The Mob Rules and Live Evil), who had left the band after the Live Aid reunion. Singer would participate in the recording of the albums Seventh Star and The Eternal Idol. In 1987, he was invited to join Gary Moore to tour in support of his album, Wild Frontier. After the tour, he was invited by his Black Sabbath colleague Ray Gillen to join Badlands. Singer accepted and played on the band's self-titled debut album. Singer left the group in 1989 as he would join Paul Stanley as his touring drummer on his solo tour of the United States and Canada. Singer played with Olivia Newton-John in the music video for "Culture Shock". He later revealed in an interview that he obtained that gig because he was working for Lita Ford at the time. In 1989, he joined Alice Cooper to tour in support of his album, Trash, as well as appearing in its music videos.