​Mariano was born and raised in Argentina, where he trained and competed alongside well-known top-ranking Argentinian players. His top junior ranking was 16th, and his highest professional ranking was 41st — he played pro tournaments against several ATP-ranked players, picking up wins along the way. His coaching career began at the Vilas Racket Club in Buenos Aires, and he later taught at the John Newcombe Tennis Ranch in Texas, developing top juniors who went on to become Division 1 collegiate players. Mariano has served as tennis director at some of the largest clubs in the country, including The Crandon Park Tennis Center in Florida, and is now the USPTA® Director of Tennis at Foothills Club, where his passion for the club's member-run, family-oriented community shows in every lesson.