In the past the company Fedex company was about to go broke, and the CEO played blackjack in order to sustain his company and now Fedex company is very successful.

If one works there, is their money halal? Like even if the origin of the business included haram money?

Gambling or playing Fam fling cards is haraam. Maybe he made money but many lose. The money is also not pure.

The salary is pure