[1] McMillan was named to the league All-Academic team as a senior, and he graduated from Birmingham-Southern in 2007 with a degree in education services.
In 2020, Mountain Brook was ranked 13th in the top 25 public high school basketball programs in the United States over the previous ten years.
[3][1] On April 6, 2020, McMillan was hired as head coach at Samford, replacing Scott Padgett.
[3] His former coach at Birmingham Southern, Duane Reboul, came out of retirement to join McMillan's staff as a special assistant at Samford.
[6] McMillan drew attention for his uptempo and aggressive style of play, nicknamed "Bucky Ball", and his team posted a 96–83 upset at Belmont on December 5, 2020.