The World War II veteran retired from the United States Army at the rank of colonel in 1974.
[2] Then with the outbreak of World War II, Denecke joined the Army and served with the 70th Infantry Division from 1941 to 1945.
Denecke left the firm in 1959 when he was appointed as circuit court judge for Multnomah County by Governor Mark Hatfield.
[7] Additionally, Denecke was a trustee for both the Oregon Graduate Center (now part of OHSU) and Reed College in Portland.
[8] While on the bench he wrote many opinions including Seattle-First National Bank v. Oregon Pacific Industries, 262 Or.
[2] After leaving the court he was an advocate for school reforms[9][10] and led an investigation of Oregon's State Accident Insurance Fund.
[2] The Marion County Bar Association gives the Arno Denecke Award annually to attorneys for pro bono work.