He was born into the family of two great chess players in the history of the Republic of Moldova. His mother, Bronea Mosionzhik, was 1 times the champion of the Republic of Moldova (1959, 1960, 1961, 1962, 1963, 1964, 1965, 1967, 1968, 1970 and 1973), but also the winner of the 1963 USSR Armed Forces Championship. His father, Ilia Mosionzhik, is a master in chess sports, a FIDE master, Champion of the Republic of Moldova in chess (1961). Alexander Mosionzhik graduated the Tula Polytechnic Institute in 1983 with a degree in applied mathematics. Candidate for technical sciences. During the years 2001-2006, he was general manager of the NAFTA company, Moscow; subsequently, starting with 2006, he was the chairman of the Board of Directors of Joint Stock Company Polimetal. Since 2009, he has been a member of the Board of Directors of Joint Stock Company PIK Group of Companies; since 2009, he has been elected a member of the Board of Directors and vice-president of the Board of JSC "Полюс Золото"; since 2010, he is a member of the Board of Directors of JSC "Международный финансовый клуб" (International Financial Club); since 2010, he became vice-chairman of the Board of Directors of JSC UralKaliu, a member of billionaire Suleiman Kerimov's team, and led to the creation of large, multi-billion dollar companies and the expansion of business in several branches of industry. His fortune is of hundreds of millions of dollars.