[2] Following his graduation from Hastings in 1995, McCaslin taught at Benson High School in Omaha, Nebraska, also serving as an assistant football coach.
In 1997 he became a graduate assistant at the then-NCAA Division II University of Nebraska Omaha (UNO) of the North Central Conference under head coach Pat Behrns, inaugurating a 14-year tenure at that institution.
[7][8] McCaslin eventually landed at Drake University in Des Moines, Iowa, as defensive coordinator for the 2012 season, after reaching out to head coach Chris Creighton.
[3] When Creighton departed Drake for the Eastern Michigan University head coaching job after the 2013 season, he brought McCaslin with him as his new defensive coordinator.
[9] Before the start of the 2014 season Eastern hired Keen, recently interim head coach at Minnesota State University, Mankato, as special teams coordinator.
[11] Eastern Michigan struggled on both sides of the ball during Creighton's first two years, to the point that the faculty union and student government would question the viability of continuing the program in early 2016.
[13][14] The University at Buffalo, also a school in the Mid-American Conference, hired McCaslin as a defensive analyst for the 2016 season under head coach and former fellow UNO assistant Lance Leipold.
[3] After two seasons in Buffalo, McCaslin accepted the heading coaching job at Benedictine University in Lisle, Illinois, which competed in the NCAA Division III Northern Athletics Collegiate Conference.