Jerelle Jules had reached the final interview stage with the hotel when he was sent its employee grooming policy.
The 30-year-old said he was later told that a black hair stylist from The Ritz had approved the policy phrasing.
Mr Jules said the document indicated "institutional racism".
Mr Jules, from Hammersmith in west London, applied for a dining reservations supervisor job two weeks ago and was due to attend the final interview when he was sent the policy document.
It stated that staff could not have "unusual hairstyles such as spiky or Afro-style".
Mr Jules, who works in corporate housing, said it was the first time he had been told he could not have Afro hair for a job, and he declined the final interview.
He said the personal grooming policy, dated to 2021, was an example of "corporate ignorance".
"I want to make sure that things like this don't happen again," he said. "It's about inclusivity and black professionalism."
Mr Jules said he had invited The Ritz to talk about diversity and being "open to all candidates".
A spokesperson for the five-star hotel said: "The Ritz London does not condone discrimination of any form and we are genuinely committed to fostering an inclusive and non-discriminatory environment for all of our colleagues and guests."
Andy Slaughter, Labour MP for Hammersmith, told the BBC that the hair policy was "blatant discrimination".
"The response by The Ritz on being challenged is wholly inadequate," he said. "They have not explained how this racist and demeaning policy came about or what they now intend to do to address its legacy.
"Mr Jules has offered to help them improve their recruitment process, which is a generous offer and one they should take up. There is no room for this type of attitude from employers."