Mirel was born on June 17, 1930 in the small town of Pascani (about 70 km East to Iasi), being the unique child of Sami and Nutza Horodniceanu. In 1940 the family moved to Bucharest. His father died in 1946.
Mirel graduated in 1953, with a degree in Electrical Power Engineering, from the Politechnic Institute of Bucharest, and received the Power Engineer Degree in 1954. He worked as an automation engineer in the Bucharest Power Stations Enterprise and in a Research Institute in Bucharest till 1970, when he immigrated with his mother in Israel.
In Israel he established himself in Haifa and began to work for the Israel Electric Company, in the Power Station Planning Division. He married Liana Saxone in March 1973 and changed the family name from Horodniceanu to Horodi (the same name that was adopted earlier by Meir Horodniceanu-Horodi). Mirel and Liana have two sons: Shmuel, born in 1974 and Miron, born in 1977.
Mirel had a brilliant career in the Israel Electric Corporation. He was appointed Head of the Electrical Planning Department in 1985 and Manager of the Power Station Planning Division in 1993. In these positions he participated in the planning of the big power stations in Ashdod, Hadera, Ashqelon, Hagit, Ramat Hovav, etc. In 1995 he retired from the Israel Electric Company, but continued to work as a Project Manager for a private company, Energy Horizons, belonging to the Ofer Brothers Group, till 2003 when he retired definitively.