He served as an administrative assistant to Congressman Glenn Cunningham, and he worked as the Director of Public Relations at the Commercial Savings Association in Omaha, Nebraska.
[3] He was active in his community and served on the board of directors of St. Vincent De Paul Stores, St. John's Seminary Association, Q Street Merchants, the National Conference of Christians and Jews, and Citizens for Decent Literature.
While Nebraska Governor Frank B. Morrison, a Democrat, was attending a conference in Hawaii, Lieutenant Governor Dwight W. Burney, a Republican, appointed Mahoney, at that time a Republican, to a seat in the legislature to fill a vacancy created by the resignation of Senator John P.
According to his obituary, he used his connections at the capitol "to persuade lawmakers to enact a park-entry permit and devote a portion of cigarette tax revenue to building park roads.
Eugene T. Mahoney State Park, located on the Platte River, off Interstate 80, approximately four miles (6.4 km) east of Ashland, Nebraska, is named in honor of him.