In 1900 following the departure of his brother he became head of the stenographers’ office, a position he kept until his retirement in 1937, having reached the rank of general director.

[1] Mindler devoted significant time promoting the education and development of Greece's youth through activities such as sports and scouting.

He was a member of the board of the Panhellenic Association of Amateur Athletics (SEGAS) when it was first established and served as its president from 1914 to 1926.

In addition, as a philatelist he served as a president of the Hellenic Philotelic Society (1929), and as a graduate of the Athens Conservatoire he participated in a number of its concerts.

[2] Every year since his death the Scout Group that he founded has laid fresh red and black tulips on his grave during a dedicated memorial service.