Killian attended Brandon High School, where he practiced football and track.
As a senior, he was the starter at left tackle, before being lost for the season with a knee injury he suffered in the fourth game against the University of Kansas.
Killian was selected by the Dallas Cowboys in the 16th round (413th overall) of the 1974 NFL draft.
He was considered to be a very good athlete, in the season finale against the Oakland Raiders, he tackled linebacker Phil Villapiano from behind, after he returned a Cowboys fumble 27 yards.
[5] On August 13, 1975, Killian was claimed off waivers by the San Diego Chargers.