From Paragon Wiki, The Midnight Squad was founded in the 1920s. Making Tommy about 50 to 60 when Numina was born as her birth is marked in the 1960s.
I would Imagine that Tommy was among one of the founders, along with Dream Doctor, Pontice Doub and some others.
Most of the members died during the first Invasion. Though it seems that the main founders probably dies years earlyer.
Its all on Wiki but you can learn most from the midnight arcs and the clickies for the Archivist badge.
WARNING: I'm not going to spoiler this out with the big white font color of doom so if you don't want to have a story spoilt look away now!!
OK so I know Numina (Tammy Arcanus) and her father (Tommy Arcanus) were both members of the Midnight Squad. Question is how did they get into the Midnight Squad? Or is this completly unknown? I'm just a bit curious