At least some content in this article is derived from information featured in Fantastic Beasts and Where to Find Them (film). As such, spoilers will be present within the article.
Director of Magical Security is the chief security officer for the protection of the magical community of North America and a high-ranking position within the Magical Congress of the United States of America, likely a rough equivalent of the No-Maj post of Secretary of Homeland Security. Thus, the Director of Magical Security was likely responsible for protecting the American wizarding community and ensure the safety of U.S. wizards. This would include overseeing the efforts to conceal magic from the highly suspicious No-Majs by among other things supervising the Federal Bureau of Covert Vigilance and No-Maj Obliviation and the division distributing wand permits with which the Congress sought to disclose the identity of criminals, which would also play a part in keeping the wizarding society of the USA safe from such individuals. .
In 1926, Percival Graves, a former Auror, served as Director of Magical Security in addition to holding the office of Head of the Department of Magical Law Enforcement under President Seraphina Picquery, in which capacity he was described as the President's "right-hand man". As such, he presumably had even many more duties on his plate than safeguarding the community in this manner, though it seemed to be considered his most important duty.
Notes and references
|Magical Congress of the United States of America|
Josiah Jackson (1693-?) · Charity Wilkinson · Thornton Harkaway (c. 1760) · Able Fleming · Elizabeth McGilliguddy (c. 1777) · Emily Rappaport (c. 1790) · Seraphina Picquery (1920-1928) · Samuel G. Quahog (c. 2014)
Wilhelm Fischer · Theodard Fontaine · Gondulphus Graves · Robert Grimsditch · Mary Jauncey · Carlos Lopez · Mungo MacDuff · Cormac O'Brien · Abraham Potter · Berthilde Roche · Helmut Weiss · Percival Graves
Department of Magical Law Enforcement · MACUSA Surveillance Wizarding Resources Department · Bureau of Covert Vigilance & Obliviation · Wand Permit Office · Body for Protection of Magical Species · Young Wizards Daycare Center