Smith will sit out the Nuggets' first seven games for pleading guilty to reckless driving in New Jersey. Richardson will miss two games after he pleaded guilty to drunken driving in Arizona.
Both suspensions imposed Friday are without pay. The NBA said Smith's was also for his poor driving record. Smith was involved in an accident in 2007 that caused the death of a passenger in his car.
"The commissioner's office has made it clear that it wants to set the highest standard of personal conduct for its athletes," Nuggets executive Mark Warkentien said in a statement. "We will support J.R. as he continues to deal with the tragic accident he was involved with two years ago and the consequences of his painful mistake. Being that this is strictly a league decision, we will have no further comment."
Smith, who finished runner-up to Dallas Mavericks guard Jason Terry for the NBA's Sixth Man award last season, is expected to move into the Nuggets' starting lineup with the departure of Dahntay Jones to the Indiana Pacers in free agency.