When McArdle graduated from St. Francis College in 1938, teaching jobs were scarce. Having worked part time as a student at the Dun & Bradstreet bindery, he returned there to work and took printing courses at night. Ineligible for the draft because of the aftereffects of polio, McArdle moved to DC during World War II to work for the Government Printing Office, running the ration stamp program. Soon he was running the GPO New York office.

After the war, McArdle returned to DC to work for David Lawrence, publisher of US News and World Report and the Bureau of National Affairs publications. When Lawrence sold BNA in 1946, McArdle purchased its printing plant and brought in his brother, Ed, to manage sales. The company doubled its volume in three years. By the time McArdle retired in 1980, business had grown to $12 million annually. Although sold in 1985, the company still bears the McArdle name and uses the signature Irish-green trucks.

McArdle's hallmark was service - to his customers and to his community. He served as president of the Greater Washington Board of Trade, the Printing Industry Association of America and the Washington Urban Coalition and was active in numerous civic groups.

A college classmate wrote in McArdle's yearbook, "Keep singing - and singing." McArdle never stopped singing. He was as well known for his booming Irish tenor as he was for his white hair and his ready smile. His songs and his service made a permanent imprint on the city he loved.