King George III is the main antagonist of Act I. He is the King of Great Britain and believes that the Colonies will not be successful in their revolution.
After Alexander Hamilton argues with Samuel Seabury, (“Farmer Refuted”) the ensemble sings that a message from the king will arrive shortly. Sure enough, King George III shows a strong assumption that he will win the Revolutionary War ("You'll Be Back").
However, following America's success, the king becomes rather irritated and sad, saying that America cheated with the French, and that he is now fighting with France and with Spain, referring to the Anglo-French War and Anglo-Spanish War respectively. ("What Comes Next?").
Once George Washington steps down, King George learns of this and questions who might replace him. A soldier brings news to him of John Adams, Washington's replacement, and the king recalls having met him years ago in 1785, believing him to be a "little guy" that the Americans will eat alive. Musingly anticipating Adams' presidency, King George wishes him luck ("I Know Him").
While King George does not sing again, during “The Reynolds Pamphlet,” the king jeers at Alexander Hamilton alongside Thomas Jefferson and James Madison. The three of them throw pieces of paper around the stage and mock Hamilton.
Throughout the show, King George III seems to progressively grow more insane, claiming that "When push comes to shove, I will kill your friends and family, to remind you of my love.” In fact, the king did suffer bouts of insanity which many have claimed to have been porphyria, and some say that his medicine, which contained large amounts of arsenic, worsened his condition. 
Notable Casting Changes Edit
Rory O'Malley took the role of King George III from Jonathan Groff on April 11, 2016. However, Groff returned to the show for one performance, which was filmed.
On January 17, 2017, Taran Killam stepped into the role of the king and ended his run on April 13, 2017.
During the interval between Taran Killam's final performance and Euan Morton's first one, the role was played by different cast members, including (from April 14, 2017 – July 16, 2017) Brian d’Arcy James. 
Hamilton Chicago Edit
Hamilton West End Edit
In December 2018, Jon Robyns donned the crown of King George III, and will end his run on November 4th, 2019.
- ↑ https://www.history.org/Foundation/journal/Spring10/king.cfm
- ↑ https://en.wikipedia.org/wiki/Hamilton_(musical)#Notable_cast_replacements
- ↑ https://www.imdb.com/news/ni59089802
- ↑ https://www.ibdb.com/broadway-production/hamilton-499521
- ↑ https://www.broadway.com/buzz/189127/euan-morton-will-don-the-crown-of-king-george-in-hamilton/
- ↑ https://www.ibdb.com/broadway-cast-staff/thayne-jasperson-491592
- ↑ http://www.playbill.com/article/breaking-leads-announced-for-chicago-hamilton
- ↑ https://www.reddit.com/r/hamiltonmusical/comments/7vs68i/hamilton_cast_update_february_2018/
- ↑ http://www.abouttheartists.com/artists/5682-andrew-c-call
- ↑ http://www.abouttheartists.com/productions/92966-hamilton-at-the-privatebank-theatre-2016-2020
- ↑ http://www.abouttheartists.com/artists/615566-jose-rosario-jr
- ↑ http://www.abouttheartists.com/characters/136913-king-george-in-hamilton-by-lin-manuel-miranda
- ↑ https://www.londontheatre.co.uk/theatre-news/news/new-cast-announced-for-hamilton-in-the-west-end