[2] In 1977, Callaway was appointed an Honorary Officer of The Order of the British Empire (OBE) and invested by Ambassador Peter Jay on behalf of Queen Elizabeth II.

[4] While pursuing his advanced studies, Callaway was organist and choirmaster at St. Thomas Chapel in New York (1930–1935) and later St. Mark's Episcopal Church in Grand Rapids, Michigan (1935–1939).

[4] He was quite short in stature, necessitating the installation of a custom-made adjustable pedalboard operated hydraulically so that the diminutive organist could comfortably reach the pedals of the Washington Cathedral's organ.

He was a guest conductor of Washington's National Symphony Orchestra and also conducted the world premiere of Gian Carlo Menotti's ballet, The Unicorn, the Gorgon, and the Manticore in 1956.

[8] Callaway's works include The Great Organ of Washington Cathedral, recorded in 1974, An hymne of heavenly love, composed in the late-1930s while at St. Mark's Episcopal Church in Grand Rapids.,[5] and "Hark!