As governor, he initiated a series of tax and legal reforms, including many that restored the rights of the native population to practice their culture more freely.

[1] In Guam, Sewell became seriously ill with an intestinal disorder, and was brought to San Francisco, California, for treatment aboard USS Supply.

[1] His first post after graduation was aboard USS Congress, where served on a mission to deliver supplies to the Polaris expedition and then to receive a visiting Russian fleet.

[1] Following the Virginius Affair, Congress sailed to Key West, where Sewell took part in several drills and exercises on the Florida Bay before returning to Norfolk, Virginia, aboard USS Ticonderoga.

[1] In April 1891, he relinquished command of the Mare Island Observatory and reported for a tour of China aboard USS Lancaster.

From July 1894 to May 1897 he once again commanded the Mare Island Observatory, where he was placed in charge of accurate time keeping for the West Coast of the United States and distribution of marine chronometers to ships in the Pacific Fleet.

[2] He also repealed a number of laws limiting the practice of native Guamanian culture, including once again allowing United States military personnel to live among the Chamorro people and allowing the Caroline Islands to wear native clothing and participate in cockfights.

[2] At first, he raised the property taxes, which had only been one percent under Spanish rule, which caused many natives to default and lose their land.

[6] After a series of crop failures caused economic hardship on the island, he reduced property taxes by fifty percent.