In more recent years, under Adam Silver's tenure as commissioner, other people involved with NBA teams beyond just the players have faced serious punishments for their actions themselves.
However, players are also eligible for long-term suspensions or permanent bannings in the event they do something egregious themselves under Silver's tenure, such as O. J. Mayo for substance abuse or Jontay Porter for gambling purposes.
The first major instance of permanent bans being used throughout the NBA revolved around the case of the CCNY point-shaving scandal that primarily happened in 1951.
By 1961, thanks in part to former player Jack Molinas, a greater scandal within the NCAA would lead to even more individuals from a mostly collegiate background (with some involving younger individuals at the time whose main crime in the event was just mainly meeting up with Molinas or one of his associates at the time) getting permanently banned from the NBA, including some players that would later get drafted into the NBA and a future Basketball Hall of Famer.
Most cases where a player has been banned from the NBA but later reinstated are a result of the league's anti-drug policy, which was started back in 1983 after a rise in drugs like cocaine and methamphetamine had occurred.