Lynch came from a family of Irish origin, settled on the Río de la Plata region since the 18th century, descendants of Patrick Lynch from Galway. He spent his childhood and adolescence in his grandfather's, Ventura Lynch, large country estate. After the estate was sold, the family settled in La Plata, newly-built capital the Buenos Aires Province. Lynch was a life-long recluse à la Emily Dickinson, living all his life with two unmarried sisters in a large old house in La Plata.
An eccentric, Lynch's quirky short stories, (he wrote more than a hundred) in a neo-gauchoesque manner that sometimes evokes magic realism, have been often filmed and dramatized. He also strikes a genuinely and authentically popular vein.
He was also a sport fan. He played football (soccer) in 1901. He played in the first organized match recorded in La Plata. He was a member of oldest club in La Plata, Club de Gimnasia y Esgrima La Plata, and he played the first game ever organized by the club that is currently the oldest club in America (founded in 1887) that practice professional soccer.