Plant was born in West Bromwich to parents Robert C. and Annie C. (Cain) Plant, but grew up in Halesowen, formerly in Worcestershire, now part of the Metropolitan Borough of Dudley. Plant gained an interest in singing at a young age.

When I was a kid I used to hide behind the curtains at home at Christmas and I used to try and be Elvis. There was a certain ambience between the curtains and the French windows, there was a certain sound there for a ten year old. That was all the ambience I got at ten years old... I think! And I always wanted to be a certain, a bit similar to that.

He left King Edward's School in Stourbridge in his mid-teens and developed a strong passion for the blues, mainly through his admiration for Willie Dixon, Robert Johnson and early rendition of songs in this genre. He abandoned training as a chartered accountant after only two weeks to attend college in an effort to gain more GCE passes and to become part of the English Midlands blues scene. "I left home at 16", he said "and I started my real education musically, moving from group to group, furthering my knowledge of the blues and of other music which had weight and was worth listening to."

Plant's early blues influences included artists such as Robert Johnson, Bukka White, Skip James, Jerry Miller and Sleepy John Estes. Plant did various jobs while pursuing his music career, one of which was working for the major British construction company Wimpey in Birmingham in 1967 laying tarmac on roads. He also worked at Woolworths in Halesowen town for a short period of time. He cut three obscure singles on CBS Records and sang with a variety of bands, including The Crawling King Snakes, which brought him into contact with drummer John Bonham. They both went on to play in the Band of Joy, merging blues with newer psychedelic trends. Though his early career met with no commercial success, word quickly spread about the "young man with the powerful voice".

In 1968, the guitarist Jimmy Page was in search of a lead singer for his new band and met Plant after being turned down by his first choice, Terry Reid, who referred him to a show at a teacher training college in Birmingham— where Plant was singing in a band named Hobbstweedle. Page explained:

When I auditioned him and heard him sing, I immediately thought there must be something wrong with him personality-wise or that he had to be impossible to work with, because I just could not understand why, after he told me he'd been singing for a few years already, he hadn't become a big name yet. So I had him down to my place for a little while, just to sort of check him out, and we got along great. No problems.

According to Plant:

I was appearing at this college when Peter and Jimmy turned up and asked me if I'd like to join The Yardbirds. I knew The Yardbirds had done a lot of work in America - which to me meant audiences who would want to know what I might have to offer - so naturally I was very interested.

Plant and Page immediately hit it off with a shared musical passion and after Plant joined the band they began their writing collaboration with reworkings of earlier blues songs, although Plant would receive no songwriting credits on the band's first album, allegedly because he was still under contract to CBS Records at the time. Plant brought along John Bonham as drummer, and they were joined by John Paul Jones, who had previously worked with Jimmy Page as a studio musician. Jones called Page on the phone before they checked out Plant, and Page hired Jones immediately.

Initially dubbed the "New Yardbirds" in 1968, the band soon came to be known as Led Zeppelin. The band's self-titled debut album hit the charts in 1969 and is widely credited as a catalyst for the heavy metal genre. Plant, however, has commented that it is unfair for people to think of Zeppelin as heavy metal, as almost a third of their music was acoustic.