I could see Castellano being a loanshark at one point but his bread and butter was the butcher trade, which he probably was pushed into by his father and uncles. His conviction for robbery in the 1930s was likely a "teenage spur of the moment crime" to make his bones in a bid to impress his buddies. There is no evidence of Castellano being a "blue collar criminal". He became the president of the Allied Retail Butchers Association and also operated The Emcee Meat Market Co before also going into the construction business. He and his partners made tons of money, with the help of "strong arm tactics" I´m sure.

Another thing that needs to be said is that the Family was not divided into one what you call "white collar" and one "blue collar" faction. Where the heck does that assertion stem from? The line between the two factions was not that clean cut. Both factions had members active in both white collar and blue collar crimes.

EDIT - Something I forgot to mention... Castellano was the acting boss sporadically starting in 1967. Jimmy Brown was the acting underboss in around 1973-1976. Before him it was Mike Caiazza.