During his career in Hawaii, he served in many political and judicial posts including circuit judge and police court judge, member of the Board of Commissioners to Quiet Land Titles, a multiple-term representative in the Hawaiian legislature, Speaker of the House of Representatives, Associate Justice of the Supreme Court of Hawaii and Minister of the Interior.

He settled permanently in Hawaii and accepted an appointment as a member of the Board of Commissioners to Quiet Land Titles, succeeding Samuel Kamakau.

However, unable to find a suitable replacement for his justice seat, the king reappointed him to the Supreme Court from February 16, 1864, to his death on March 12, 1867.

[4] In 1851, George Morison Robertson married Sarah Symonds Humphreys, an Englishwoman from Brighton who was shipwrecked with her family at Waikiki while they were traveling to the California Gold Rush from Australia.

[1][13][14][15] They had seven children including three sons and four daughters:[1][16] Robertson was initially a Presbyterian, the religion he was brought up in, and worshiped at the Seamen's Bethel Church under Reverend Samuel C. Damon.

The king, the court, government and diplomatic officials, Honolulu residents and officers of the USS Lackawanna took part in the funeral procession.

It will be impossible to fill the vacant judgeship with a man of the same varied qualifications, for there is no one living possessed of the knowledge of the native language combined with the firmness, impartiality and virtue which he had.