According to the publisher Edwin S. Brill, New York City, Sam Jackson was an eccentric colored character who together with his sister Alamanda composed the cakewalk Sam Will Oblige (1905). It is the only known published work to which they are credited, strongly suggesting that a pseudonym has been used here and one wonders who the real composer was.
For data housekeeping purposes he is listed in these webpages as a one-off composer.