The third in line to the British throne, who turns 1 on July 22, was helped along by mom Catherine, Duchess of Cambridge, as he took a few tentative steps on the sideline green before succumbing to the ease of crawling.
The casually dressed duchess was seen toting the boisterous tot in several photos.
George was clad in a white shirt and red overalls as he played with a soccer ball and grabbed at a polo mallet. His mom and dad also took him to meet
It was an "impromptu family day out," Clarence House told the BBC.
Prince William and his brother
Wills competed in the polo match last year as well, just as his son's birth was imminent.
On Monday, William and Kate donned their finery to join
Founded by King Edward III in 1348, it is the oldest and most exclusive British order of chivalry. The group's companions, limited to 24, are appointed by the monarch.
Charles, Prince of Wales, and his son walked in an elaborate procession and later joined Kate in an open carriage as they left the installation ceremony at St. George's Chapel in the castle.
Mervyn King, former governor of the Bank of England, and Eliza Manningham-Buller, former head of Britain's MI5, were the two new members appointed to the order on Monday, according to the BBC.