A former head coach for the Seattle SuperSonics and Portland Trail Blazers, McMillan is filling one of the two vacant spots on Vogel's bench after Brian Shaw was hired as coach of the Denver Nuggets and Jim Boylen left to become lead assistant under Gregg Popovich with the San Antonio Spurs.
Vogel said earlier this week he wanted to move quickly to fill his assistant jobs, with one of the priorities being finding someone who can relate to a young roster. In addition to his coaching experience, McMillan also played 12 years in the NBA.
McMillan has a 478-452 record in 12 seasons as coach, making the playoffs five times. He also was an assistant under Mike Krzyzewski for the United States national team that won a gold medal at the 2008 Olympics.
The Pacers pushed the Miami Heat in the Eastern Conference finals, losing in seven games.