Great concept for a list! Some other NBA people who were involved in four or more decades: Don Nelson, Larry Brown, Phil Jackson, Kevin McHale, Wes Unseld, Doug Collins, Gregg Popovich, Paul Silas, K.C. Jones, Rudy Tomjanovich, Jason Kidd, Larry Bird, Red Holzman. There are others but that's who comes to mind.

If you include front office stuff like GM and team owner you can add Michael Jordan, Magic Johnson, Elton Brand, Grant Hill. 

Thanks Billy.   My basketball knowledge is not the best.  Suggestions appreciated,

My original intent was to include a player/coach/manager who spanned 4 decades in one discipline.  So, for example, in hockey, Wayne Gretzky player 1979-99 and coach 2005-09 doens't qualify.

Yes, Phil Jackson is a glaring omission, coaching from 1989-2011.

No disrespect to Larry Bird (one of my favourites) but he is "only" a 3 decade player (1979-92), so like Gretzky, he doesn't make the list.

I will add the others who make the cut.

Added  Don Nelson, Larry Brown, Phil Jackson, Gregg Popovich, Paul Silas, Red Holzman. 

Added Darryl Sutter.

Added several NHL and NBA coaches.

Added NFL coaches, Phillips, Carroll, Gruden, Shanahan.

Nick Altrock? Five decade player?

Slight correction to list:  Mike Morgan began his ML career in 1978, not 1976.  I remember the A's bringing him in to start right out of high school.