Pinkham arrived in Hawaii in 1892 to build a coal handling plant for Oahu Railway and Land Company, and then went to California in 1894.

While president of the Board of Health, he developed the idea of dredging the marshlands of Waikīkī via a two-mile long drainage canal.

Over his two terms, Pinkham's achievements included improving the conditions of the lepers at the Molokai settlement, economically reducing the occurrence of bubonic plague and cholera in Hawaii.

After four years, the HSPA ended Pinkham's contract "because of differences of opinion about the methods and purposes of recruiting Filipino workers.

[2] In 1917, during Pinkham's governorship, the deposed former monarch of the Hawaiian Islands, Queen Liliʻuokalani, died and was buried at the Royal Mausoleum of Hawaii.