Suffering physical abuse as a child, Jesus Christ Superstar actor and short-lived Black Sabbath frontman turned to theft and playing in rock bands to escape his personal pain.
"I grew up filled with hate and violence," Jeff says.
Breaking into homes and joy-riding in stolen cars, Jeff's mother warned police that he was uncontrollable and he spent time in jail between the ages of 12 and 17.With his love for rock 'n' roll, at just 15, his record Gone to Far was number one in the Midwest and a US Top 40 hit. A second hit 1000 Devils followed. Two years later, he was signed by CBS Records and began touring full-time.
During an unusual night off and shortly after punching up a surly stranger in the street, Jeff heard someone quoting from the Bible for the first time in his life.
While listening to the Christian preacher, he says, "Something touched me deep inside" as he had been searching for God since childhood.
Then, after being bussed to the church along with drunks and drug addicts, Jeff recalls feeling pressured by the preacher into accepting Jesus, but received a shock when he went forward.
"I asked Jesus, 'If you are Lord show me'. Then I began to feel the power of God touching my heart and soul."
Seeing his rockstar appearance, the preacher told Jeff, "Come back in a week, if you still want to accept Jesus" and offered him a book to read.
Jeff reacted bitterly to what he perceived as rejection and never returned to that church. That night Jeff was terrified by an evil presence and a demonic voice telling him he would play Jesus in the stage production Jesus Christ Superstar.
That same year, in 1971, his wife Reeni became a practising Christian, but he did not know it then.
In October, Jeff would star as Jesus in the Jesus Christ Superstar, beginning with the world premiere at the Mark Hellinger Theatre in New York.
Before a show in Boston Gardens, Jeff recalls, "I felt some evil presence consumed me and take charge of me back stage, it filled me with fear and power at the same time. This presence stayed with me for nine years."
In just six months, the show netted US$36 million, not including music royalties.
Back stage, he was visited by disturbed people. One asked him to resurrect a dead spouse, another was blind from birth yet she described the attire of the whole cast.
"Let's face it, Jesus was not the author of that stuff," he explains, adding that this occurred because he hated Christians and cursed them whenever they told him about the Lord Jesus Christ.
Falling ill from excessive partying, the doctor later ordered Jeff to rest at home for six months.
During this time he made a couple of records but got so messed up on drugs trying to suppress his panic attacks that he beat Reeni unconscious in their home.
"Do you know how demonic I was?" he remembers sadly. "I didn't call a doctor or friend [after beating Reeni], instead I went to sleep."
The next day, Jeff discovered that her friends had taken her to hospital. Days later, his wife returned out of love for him.
"She kept calling on Jesus [to deliver me]," Jeff remembers.
Despite everything, God was not done with him yet. Among the crew who had come to do home renovations for him, lead contractor Nick Disipio began some spiritual renovations in Jeff too.
Noticing a demonic presence in the house, Nick, a former Mafia mobster turned drug rehab leader, approached the shirtless, gold-laced Jeff with groomed waist-length hair and asked, "You played the part of Jesus Christ, now do you want to meet the real Jesus?"
Enraged and retorting with curses, Jeff ran away shaking uncontrollably.
"Finally, I went downstairs and said to the workers, 'I will not accept Jesus, but if you want to pray for me, you can pray for me.'"
The team immediately prayed for Jeff, and moments later he recalls feeling something like the "weight of the world" lifted from his back.
"If this is Jesus, I want to accept Jesus as my Lord and Saviour," Jeff told them.
He was baptised at the beach that day to symbolise this commitment.
"The Lord miraculously delivered me from drugs and alcohol, but deep seated bitterness was a hard thing for me to work through."
Jeff says he also struggled to stop worshipping money or make music with ungodly themes.
The dangers of this became clear when, while making a rock album, Jeff's best friend Felix Pailardi and drummer Gary Driscoll were murdered.
He also put money into so-called 'Christian investments' and after two severe losses, Jeff says, "The Lord showed me that I had put my trust in other men instead of Him."
After these losses, Jeff admits that he went back to making secular rock music as lead singer for mega rock band Black Sabbath for six months of 1985.
Coming to his senses, Jeff remembers thinking, "I've been in the biggest rock groups in the world, but I can't get blessed in these groups anymore because I am not of the same spirit."
He left the band because, "I could not live one minute without my Saviour."
Since then, Jeff has been telling others that submitting everything to Jesus is better than anything else in this world.
"The incredible power of Christ's forgiveness and compassion has led me into a whole new ministry to those who have also suffered abuse or have been bound by bitterness, violence, or drugs," he concludes.