Nicolae Marcoci was born in Iași. He began riding in 1948 and was a member of the CSA Steaua București team from 1950 to 1964 during which time he won seven Romanian titles in equestrian. In 1956, Marcoci was a member of the Romanian Olympic dressage team which competed in Sweden and finished eighth in the team competition. Marcoci later served as a coach with CSA Steaua for over 20 years, until 1978. He was also awarded the title of master of sports.
His son, Radu was also highly successful in the sport, winning 18 national titles in dressage and three Balkan regional competitions. He was the Romanian national dressage trainer from 1991 until his immigration to the United States in 1996 where he owns and operates the RoAmerica Dressage Academy.