ANSWER: I don't know much about him, but he was someone who helped compile and edit the dictionary.
I love my Dong-A's Prime Korean-English Dictionary and am impressed with how much effort was put into it by a Sogang University English Language & Literature professor named Kim Yong-gwon (김용권) and a William Burns, who apparently was also an English professor at Sogang University.
UPDATE: According to information HERE, a William T. Burns "arrived [at Sogang University?] on September 8th, 1965 and said that he would 'teach English as a volunteer for one or two years.' He left Sogang in late May 1999 to enter a Trappist monastery in the United States," which means that he stayed for more than just one or two years.
So, according to the above source, William T. Burns arrived in Korea in 1965, but the caption under the following photo of William T. Burns, from the source HERE, suggests that he taught at Sogang University from 1978 to 2002. The haircut, glasses, and suit, however, look 1960s to me. It might be that Mr. Burns arrived in Korea in 1965 but did not start working at Sogang University until 1978.
Anyway, the following is a Korean-language video, with English subtitles, commemorating the 60th Anniversary of Sogang University. In the video, there is an interview with Professor Emeritus Kim Yong-gwon and other Sogang University professors who remember the early days at the university. The interviews are somewhat interesting.