Word choice for describing people

Is there a word or phrase in English that describes people who always prioritise self-interest over other matters, have a weak sense of responsibility, and are inclined to find excuses?

For example, as a manager, you ask this guy to complete the task 100% and he promises to do it. But later, it turns out that he has just finished 90% by the due date and gone for a vocation. You then complain to him and he replies, "It doesn't matter. Just 10%!". Then, you might want him to come back and fulfil his promise, but he suddenly gets very upset and says, "Fine! You are so annoying!". How would you describe this kind of person according to his behaviour, imagining that it happens often?

how about :

self-serving

adjective

having concern for one's own welfare and interests before those of others. "public accountability is replaced by self-serving propaganda"

noun

concern for oneself before others.