He implemented the modernization of signal units from the usage of just wire and radio, through the growth of strategic satellite communications, to the integration of computer systems at even the tactical level.

In 1945 he attended the Command and General Staff College, then taught at the Signal School in Fort Monmouth, New Jersey.

After this, he was assigned to the Joint Planning and Army Logistics at the Senior United States Headquarters at Honolulu, Hawaii.

[3] Approaching retirement from army life, he attended seminaries in Washington, D.C. and Louvain, Belgium and was ordained a Roman Catholic deacon in April 1979 by Cardinal Terence Cook in Heidelberg, Germany.

[3][6] Rienzi died on December 15, 2010, at Tripler Army Medical Center, Honolulu, Hawaii, and was buried in the National Memorial Cemetery of the Pacific.

Rienzi commanded units of the United States Army's most technical branch during the transition from wire and cable, vacuum tube radio and visual signals, through the advent of transistorized radio, teletype, electronically secured voice communications and satellite communications.