The governor has a duty to enforce Guam's public laws, the power to either approve or veto bills passed by the Guam Legislature, to convene the legislature, and to commute or grant pardons to criminal sentences, except in cases of treason and impeachment.

The governor is given the power to control government budgeting and appoint many officials (including many judges).

The governor may also perform ceremonial roles, such as greeting dignitaries, issuing symbolic proclamations or commencing the Liberation Day parade.

As soon as the governor takes the oath of office, four ruffles and flourishes are played then followed by "The Stars and Stripes Forever" and a 21-gun salute.

Pursuant to the Guam Organic Act, the governor's term of office begins at midnight on the first Monday of January of the year following the election.

In 1565, Miguel López de Legazpi formally declared Spanish sovereignty over the Mariana Islands.

Antonio de Saravia, who arrived in June 1681, was the first to receive his appointment as governor from the Spanish throne, meaning that, technically, he was no longer subordinate to rule from the Philippines or Mexico.