In 1965. at the age of 19, Miller left Houston, Scotland to seek his fortune in London.
He eventually joined the Keef Hartley Band in 1968 as vocalist/guitarist. He recorded five albums with the band on which he was the main songwriter. The Hartley band appeared at the legendary Woodstock festival in August 1969.

He has also worked with Savoy Brown, Chicken Shack, Marc Bolan's T-Rex & Donovan's band.
For four years he was vocalist/bassist with the popular US. band Mountain. Miller has toured as a "special guest" with Deep Purple, appearing on their live CD/DVD from the Albert Hall in 1999.

He has been a member of the Spencer Davis Group for the past fifteen years. Multi-talented from a young age, he plays guitar, slide guitar, harmonica, bass, drums and a little piano. Over the years he has been a creative and prolific songwriter. Last but not least, he is without doubt, one of the very best male vocalists to come out of the UK.