He wasn't actually the first African American to play Major League Baseball.
That would actually be Moses Fleetwood Walker. Both he and his brother Welday played for the Toledo Blue Stockings in 1884. Moses was a catcher before they had gloves, if that wasn't hard enough; he had to deal with his own pitcher (Tony Mullane) disregarding his signs in an attempt to injure him, at one point breaking one of his ribs. When asked later what he thought of Walker, Mullane responded, "he was the best catcher I ever worked with."