The 33-year-old British royal was named Captain General Royal Marines following Prince Philip's retirement from royal duties in August.
Prince Philip was appointed Captain General, the ceremonial head of the Royal Marines, in 1953, the same year his wife, Queen Elizabeth II, was coronated. He honored Prince Harry alongside Major General Robert Magowan and Major General Charles Stickland at a ceremony Tuesday.
"The Queen has approved the appointment of Prince Harry as Captain General Royal Marines in succession to The Duke of Edinburgh," Kensington Palace tweeted alongside a photo of Prince Harry, Prince Philip, Magowan and Stickland.
"Prince Harry accompanied The Duke in his final duty as Captain General today, as Their Royal Highnesses received the incoming and outgoing Commandants General @RoyalMarines at Buckingham Palace," the palace added.
Prince Harry accompanied The Duke in his final duty as Captain General today, as Their Royal Highnesses received the incoming and outgoing Commandants General @RoyalMarines at Buckingham Palace.— Kensington Palace (@KensingtonRoyal) December 19, 2017
Prince Harry served in the British Army for 10 years and has since supported a number of veterans organizations, including the Invictus Games. His appointment as Captain General Royal Marines follows news he and Meghan Markle will marry in May.
"His Royal Highness Prince Henry of Wales and Ms. Meghan Markle will marry on 19th May 2018," Kensington Palace announced last week.
Prince Harry will appear alongside former U.S. president Barack Obama in a BBC News Radio interview Dec. 27. The pair will discuss their shared interest in "building platforms for the next generation of young leaders."