Carter managed Liliʻuokalani's personal real estate holdings and had been her friend and confidant for years before she ascended to the throne on January 29, 1891. When Liliʻuokalani became regent, Carter was appointed royal adviser on the Privy Council of State. At a June 23, 1892 ceremony at
Iolani Palace when Japanese Consul-General Taigo Masaki bestowed Liliuokalani with the Grand Cross of the Imperial Japanese Order of the Crown, Carter was bestowed with Third Class Order of the Sacred Treasurer. Liliʻuokalani's proposed
1893 Constitution provoked protests, but Carter advised against her cabinet's suggestion of requesting American intervention to maintain civil order. He prepared a proclamation signed by the Queen and her cabinet that promulgation of a new constitution had been abandoned, but it was not enough to stave off the overthrow and installation of a provisional local government. Carter counseled her to resign under protest, and on January 17 she temporarily ceded her power to the United States. Following the overthrow, Carter was part of a group sent to Washington D. C. by the provisional government to plead its case for annexation. He was appointed by provisional president
Sanford B. Dole to the Board of Health. President
Grover Cleveland attempted a restoration of the monarchy, with the stipulation that Liliʻuokalani grant amnesty to everyone responsible. Over her demands of beheadings for all involved, Carter obtained her written assent to amnesty. Dole refused to re-instate the Queen, and the
Republic of Hawaii was declared on July 4, 1894. Carter's standing in the business community suffered from his association with the Queen. According to Boston author
Julius A. Palmer Jr., Carter's loyalty to her resulted in his being voted out of his position at C. Brewer & Co. The Queen was put on trial and under house arrest for her alleged part in the
1895 Robert Wilcox rebellion attempt to restore her to the throne. She was granted a full pardon in October 1896. When she left Hawaii for the United States in December, seeing her off at
Honolulu Harbor were Carter, on whose arm she leaned as she walked up the gangplank,
Robert Wilcox, and her former Minister of Foreign Affairs
Samuel Parker. At an October 1897 gathering of 2,000 anti-annexationists, Carter was the main speaker. He traveled to Washington D. C. in January 1898 to lobby against annexation. Newspaper coverage alleged he made the trip at the request of sugar plantation owner
Claus Spreckels. When Hawaii was annexed in 1898, the
Crown Lands were seized by the United States government. Liliʻuokalani spent the next several years unsuccessfully lobbying the government for return of the Crown Lands, during which she relied on Carter for legal consultation. ==Trustee-estate manager business==