The photo, which shows Charles proudly wearing 13 medals, was captioned: "Wishing a very Happy Birthday to His Royal Highness the Prince of Wales!"
Even the Royal Air Force wished him a happy birthday, sharing a photo on Twitter of the royal at RAF College Cranwell earlier in the year as the Reviewing Officer for the Sovereign's Review.
And royal fans also wished Prince Charles a happy birthday and thanked him for his years of service.
Charles responded to the tributes on the Clarence House Instagram page, sharing a photo of him wearing a green Scottish kilt.
"Thank you for all the well wishes on The Prince of Wales's 72nd Birthday!" the caption read.
But there was one tribute missing from among his family members - from Prince Harry and Meghan Markle.
The Sun reported that the Duke of Sussex did not publicly wish his father a happy birthday.
The couple stepped down from royal duties earlier this year, and may have sent private birthday wishes to Prince Charles.
Charles has guest edited another issue of Country Life magazine to mark his birthday. His last edition was in honour of his 70th birthday in 2018 - it was the magazine's biggest-selling issue in its 123-year history.