The seventy-four-year-old king presented Conservative Prime Minister Rishi Sunak's wish list of new laws, reinforcing divisions with the main opposition Labour Party, from a gilded throne in the House of Lords.
Outside parliament, a few dozen demonstrators screamed "Not my king" and "What a waste of money" as Charles addressed MPs while wearing the Royal Navy uniform, a long crimson robe, and an Imperial State Crown set with diamonds.
With a general election generally anticipated for next year, the 10-minute address was given as the Tories, who have been in office since 2010, lag Labour by double digits in the majority of opinion polls.
Charles gave his first formal speech as head of state during the ceremony, but he had practice standing in for his mother, Queen Elizabeth II, in May of last year.
It was also Sunak's first since taking over as prime minister from Liz Truss, who was in power for just 49 days after replacing Boris Johnson two days prior to the queen's passing.
Charles opened the speech by saying, "It is mindful of the legacy of service and devotion to this country set by my beloved mother, the late Queen. I deliver this, the first King's Speech in over 70 years."
In it, Sunak proposed harsher sentencing rules centered on life sentences and the elimination of early release for some violent sexual offenders, turning law and order into a major electoral battleground.
Additionally, he emphasized the distinctions he is making between the environment and energy with Keir Starmer's center-left Labour party.
In his address, Sunak proposed a rule that would yearly give new licenses for oil and gas projects in the North Sea, which he claims will lessen Britain's dependency on imported energy and generate employment.
Following the tradition that the king is above politics, Charles, who has dedicated his life to environmental concerns, made the statement without showing emotion.
In an attempt to revive his party's chances, Sunak had previously declared in September that he would be rolling back green energy regulations and presenting himself as an advocate for drivers.
Labour has declared that it will not grant any further licences for oil and gas exploration, but will instead increase funding for renewable energy sources.
Rituals: Sunak also mentioned changes to house ownership regulations and a phased smoking ban, which he introduced at the Tory conference last month.
The last male monarch to deliver the King's Speech, which marks the beginning of a new parliamentary year, was King George VI, Charles's grandfather, who was ill and was unable to do so in person in 1951.
It outlines the kinds of legislation the administration intends to pass in the coming year from parliament.
Due to their strong parliamentary majority, a Tory loss in the next election is far from inevitable, but it would mean that a large portion of the law would never be implemented.
"The public is both bored and angry at Conservative governance, and Sunak is running out of time," said Richard Carr, an associate professor of public policy and strategy at Anglia Ruskin University.
The monarch rode in a carriage from Buckingham Palace to the Houses of Parliament for Tuesday's official opening.
A 41-gun salute was among the 1,400 military personnel, 124 horses, and marching bands who participated in the events.
Charles's sister, Princess Anne, rode in the parade and ceremoniously assumed the role of Gold Stick in Waiting, the King's "protector."
An MP was customarily kept "hostage" in order to guarantee the king's safe return.
Because of the unsuccessful effort by Catholics to blow up parliament in 1605, royal bodyguards routinely examined the Palace of Westminster basement for explosives.
A custom that represents parliament's independence from the king saw the lower chamber House of Commons door slammed in the face of a parliamentary officer known as Black Rod.
Before delivering the address to the assembled lords and ladies in red robes and invited members of the elected Commons, the king led a parade through the House of Lords, the parliament's unelected upper house.