Robert John Lange's South African born father was a mining engineer, his mother a very cultured woman who came from a prosperous family in Germany. Nicknamed "Mutt" at an early age, he grew up a fan of country music, in particular the singer, Slim Whitman. Sent to study at Belfast High School in South Africa, he started a music band in which he played rhythm guitar and sang harmonies. He eventually married Stevie van Kerken (aka Stevie Vann) and moved to England where, in 1970, he started the band, "Hocus" in which his wife would sing vocals.
Beginning production work in 1976, his first major hit was AC/DC's album "Highway to Hell". He produced several more albums with the band, also working with 80's pop-rock group "Foreigner." He worked with Def Leppard on their hit albums, "Pyromania" and "Hysteria," cowriting many songs. He is often credited with bringing them to the incredible levels of popularity that they achieved.
After "Hysteria," Lange felt he had contributed all that he could to Def Leppard's career, and he decided to bow out of working with them while they were at their peak. In 1991, he produced Bryan Adams' "Waking Up The Neighbours", including "(Everything I Do) I Do It For You", a hugely-successful single (aided by its appearance of the soundtrack of the Kevin Costner film Robin Hood, Prince of Thieves).
After seeing a virtually unknown singer by the name of Shania Twain, he got in touch with her agent and offered to produce for her. They were married in 1993 and together have built her enormously successful recording career.