McCollum started his law enforcement career in 1986 with the Pulaski County Sheriff's Department under the late Sheriff Sam Catron. In 1989 he joined the Somerset Police Department as a patrolman. He held several additional assignments including detective, field training officer, D.A.R.E. instructor, crime victim's advocate and hostage negotiator.
McCollum was the author of the grants that started the department's Crime Victim's Advocate and School Resource Officer programs.
Over the years, he has received numerous awards and commendations. They include citations for valor, most criminal arrests and criminal cases, as well as his work with Arizona authorities in the apprehension of two murder suspects in 1995. McCollum was recognized by the U.S. Attorney's Office for his service to crime victims. The Kentucky D.A.R.E. Association recognized him for 10 years of service.
He currently serves on the board of directors for the Bethany House and as a region representative for the Kentucky D.A.R.E. Association.
In 2007 he was promoted to the rank of Major and served as the department's assistant chief of police.
Major McCollum enjoyed coaching Meece Middle School basketball for several years and working with youth activities in his spare time. He is a 1984 graduate of Somerset High School.