Killian coached basketball teams of Wharton High School between 1949 and 1951 and Erie Community College, Buffalo, N.Y. from 1954 to 1969. He was president of the international basketball federation FIBA between 1990 and 1998. In 1996, he was member of the International Olympic Committee in his capacity as president of FIBA. Killian served also as treasurer of COPABA, Panamaerican Basketball Confederation and director of the NJCAA, National Junior College Athletic Association.
After presiding the US delegation at the Universiades three times, Killian held office in FISU. He was member of the International Control Commission from 1975 to 1987. Then, he was elected vice president of FISU. In 1995, Killian was promoted to First Vice President. On November 26, 1999, he was confirmed as FISU President by the executive committee succeeding late Dr. Primo Nebiolo.
On August 5, 2007, Killian was reelected for a second full term as president of FISU by an overwhelming majority of the votes at FISU's 30th General Assembly, which was held in Bangkok, Thailand.
On August 9, 2011, he was replaced by Claude-Louis Gallien as FISU President.