Fortunately there are not too many assholes out there, and I believe the startup world has fewer than its fair share, but a few assholes can do a lot of damage to a small company, so it is smart to be on the lookout for them.

For purpose of this discussion, let’s define “asshole” as someone who actively undermines your team and culture. This could include:

  • Actively undermining co-workers (not just healthy disagreement or criticism).
  • Always wanting to be right and win every argument and disregarding whether their idea was the best idea.
  • Turning professional disagreements into personal vendettas.
  • Lashing out against other people and inflicting verbal abuse.
  • Disrespectful and derisory behavior toward customers and partners.

Note that because of where they fit in the power structure of the company, managers are the most likely to display asshole tendencies, and they can do the most damage to the culture when they do.

Unfortunately, standard interviews and superficial reference checks are not very reliable at exposing who might exhibit asshole tendencies when times get tough. Many assholes can be quite charming on a one-on-one setting – you only see their asshole side come out during stressful situations or when they are dealing with subordinates. But there are a few things you can try:

  • References, references, references.  References are always crucial for hiring, and, although you should start with the references they gave you (they do have a long list of positive references, right?) it is good to find other references than the ones they gave you — perhaps through mutual acquaintances.  Assholes often struggle to provide solid references, and the ones they provide may either be some of the few friends they have or might provide only vague feedback.
  • Look at resume history. Most people who work in tech end up crossing paths with some of the same people again and again since they recommend each other into their companies. Assholes often have to go back onto the open market for each job since when co-workers start companies or go to new opportunities, they don’t work hard to refer them in.
  • Listen carefully for badmouthing of previous jobs and co-workers. With assholes, you will hear a lot of answers that amount to “everyone was stupid but me,” “no one wanted to hear the truth,” etc. It is fine for them to tell you they were not challenged at their job, but when they start rolling their eyes and insulting their co-workers, that is a bad sign.
  • Listen for a lot of “I” and “me” when they talk about previous projects. Most people will talk about projects as team efforts and will be proud of their role on the team and how they worked with others. Assholes often talk as if every project were a solo effort.
  • Ask about the skills they admire and the skills they wish they had more of. Assholes usually are not very introspective or at least resist acknowledging their weaknesses. They either think they are good at everything or, more likely, think that the thing they happen to be good at just happens to be the most important skill at the company.
  • Ask about effective team construction: what mix of skills and culture do they think you need on a team to be effective. A–holes tend to rank other people on a linear, good/bad scale as opposed to thinking about how a diversity of skills adds up to more than the sum of the parts.
  • Ask about areas of previous conflicts and what they did to resolve them. Conflicts are part of the work place, but assholes will often talk about these issues as zero-sum-game encounters that could only have a single winner and a single loser, and they will talk about how they worked to come out on top.
  • Ask about leaders they admire and what skills those people have. A–holes will usually talk about leaders who act more like individual contributors (wanting to own everything and be right about everything) vs. ones that get the most from their team. Especially be on the lookout for people who think that emulating Steve Jobs is the best way to succeed – sure, if they are the next Steve Jobs, hire them, but most people are not.

And, if you do happen to hire an a–hole, act immediately. Give him tough feedback, and short time to improve, then move him on before he damages the culture you are trying to build.

Good luck!

Note, this answer originated from a Quora thread.