Chairman Keaton (previously Congress Member Keaton) is an official of the Galactic Federation. His rank in the Federation high-command is unknown, but he wields considerably high authority over the Federation Police and is seen giving orders to Chief Hardy. Keaton appears in the Super Metroid comic and the Metroid Manga.
In one scene in the manga, Keaton is seen questioning the Galactic Federation's rise to military power (fearing that they are "no different than Space Pirates"), and later speaks his mind with the Chozo, who share his sympathy. Later in the manga, Congress member Keaton becomes Chairman. During his election ceremony, Mother Brain attempts to assassinate him with an illegal bioweapon called a Mimic. The weapon is hidden in some flowers that Damara brought to him. Samus Aran saves Keaton by destroying the bioweapon with much ease.
Super Metroid guide
The profile of Samus Aran in the Japanese Super Metroid guide mentions Keaton, and states that he is the only "person who knows about her early life." The English translation of the profile can be read here.
Super Metroid comic
Keaton also appears in the Super Metroid Nintendo Player's Guide, in artwork that appears to have been reused from the comic.
Metroid: Other M
In Metroid: Other M, Anthony Higgs mentions that his orders to secure survivors were issued by Commander Adam Malkovich and authorized by the Chairman of the Galactic Federation. It is possible that this is Keaton, although his term may have expired by the time of Other M. As a corrupt colonel is having the last survivor of the BOTTLE SHIP arrested, he prohibits Samus from having any contact with her due to her unofficial status as a Bounty Hunter. However, Anthony turns up alive at the last minute, and uses his mission orders to override the Colonel's authority and take Bergman into his and Samus's legal protection.