Growing up in the shadow of Warner Brothers Studios as a kid Scott MacMillan used to regularly sneak on to the back lot to play as well as attend Boy Scout meetings at Walt Disney Studios. While still in film school a chance appearance on the Dating Game landed Scott a job at ABC TV, where he worked on a variety of shows before moving to ABC 20th Century Fox. Here he worked on Lost In Space and Time Tunnel, as well as a number of other ABC shows and movies of the week then filming at Fox.

Leaving ABC/Fox in the mid-1970s he free-lanced as an assistant director for several years, as well as writing shorts stories and editing Far West Magazine, where he won five Golden Spurs for western short fiction.

In the 1980s he and his partner Andy Ettinger were involved in the purchase of Ardmore Studios, the national film studios of Ireland. This necessitated a moved to Ireland with his wife, author Katherine Kurtz. While in Ireland Scott wrote two horror novels (Knights of the Blood and At Swords Point) while continuing to work in the motion picture and television industry on projects as diverse as the Irish TV series Ballykiss Angel; the motion picture Brave Heart, and several TV mini-series including Scarlett, Kidnapped, and Malice of Forethought.

In 2007 Scott returned to the United States and started his own production company, Deep Reach Productions. As the creative head of Deep Reach Productions he and his partners have developed a number of non-fiction shows for cable networks including Inside Stately Living, When Seconds Count, The 100 Hour Film Festival (co-production with WVPT, Harrisonburg, VA), and FUBAR (co-production with Bill Fawcett and Associates, Chicago, IL).

Scott and his wife, novelist Katherine Kurtz, currently reside in Staunton,Virginia, along with their five cats and three Basset hounds.