[1] Hickey served in the army during World War II for 42 months and received the rank of private.

Hickey seconded the presidential nomination of Lyndon B. Johnson at the 1960 Democratic National Convention.

On January 2, 1961, Gage appointed him to fill the vacancy created by U.S. Senator-elect Keith Thomson's death.

Hickey was nominated by President Lyndon B. Johnson on May 12, 1966, to a seat on the United States Court of Appeals for the Tenth Circuit vacated by Judge John Coleman Pickett.

In July 1970, Hickey was hospitalized for a stomach ulcer and in August he went to the Presbyterian Medical Center in Denver for lung cancer treatment.