Received his Ph.D. in physics from Iowa State University in 1951, then worked there as an assistant professor in meteorology. He was a research physicist in the University of Chicago's department of meteorology (1953-54). In 1954 he joined the University of Arizona faculty, first as an associate professor (1954-56), then as a full professor in the department of meteorology (1956-71). McDonald was also a senior physicist in the University's Institute of Atmospheric Physics, and served as both associate director (1954-56) and scientific director (1956-57). He also advised numerous federal agencies, including the National Science Foundation, The Office of Naval Research, the National Academy of Sciences, and the Environmental Science Service Administration. McDonald had a personal UFO sighting near Tucson on Jan. 10, 1954, with two other Univ. of Chicago meteorologists, and this launched him on his lifelong interest in UFO's. By 1958, McDonald was investigating local UFO sightings in the Tucson area. The ONR provided cover for his early UFO activities. He was told of sonar anomalies and the Navy asked him to investigate possible similar radar phenomena at Project Blue Book, which "got him in the door". Early Hall-McD correspondence shows McD was not too keen on going public. He wanted to get other research out of the way first, but once in he was in all the way. Beginning in 1966, McDonald became intensively involved in UFO research, interviewing hundreds of UFO witnesses and lecturing widely on the subject to professional societies. His talks emphasized the need for a serious scientific study, adding that he considered the best reports to be evidence of extraterrestrial visitation. He also played an important role in Congressional UFO hearings in 1968. Privately, McDonald analyzed many Project Blue Book case files, convincing him that the Air Force had performed an entirely inadequate investigation, which appeared to have been more concerned with internal politics rather than real science. He also reviewed the cases of the Air Force's sponsored University of Colorado UFO study, and concluded that many of their explanations were not well founded either. McDonald left no book but privately published many papers based on his lecture presentations.  McDonald's scientific analysis and investigation of UFOs was of the highest caliber and errors were few and far between in his work. (Swords, Sparks, Aldrich)