The ceremony was conducted in the castle's Private Chapel inside Buckhingham Palace and was presided over by the Archbishop of Canterbury Justin Welby.
Baby Archie was seen wearing the same gown his cousins, Prince George, Princess Charlotte, and Prince Louis wore at their christening- a replica of the 1841 robe worn by Queen Victoria and Prince Albert's first child, Victoria.
Prince Harry's aunts, Lady Sarah McCorquodale and Lady Jane Fellowes who were present at his wedding, were also seen in attendance at the ceremony.
In the official christening portrait released by the Sussex Royal on their Instagram account, Princess Diana's sisters, Lady Sarah and Lady Jane can be seen standing between Meghan Markle's mother Doria Ragland and Prince Harry's brother, Prince William.
The intimate gathering, which was attended by 25 close members of the family and friends also included Kate Middleton, Prince Charles, and Camilla, Duchess of Cornwall.
However, among those absent from the ceremony were the great-grandparents of Archie- Queen Elizabeth and Prince Philip.
People magazine reported that the Queen was absent due to a series of prior commitments and that she is getting ready for her summer holiday at Balmoral Castle in Scotland.
Since the Buckingham Palace is opened for tourists and visitors every year during July, the Queen prefers to spend this time in her Scottish residence where she continues to work even during the holidays.