Controversial opinion but learned through experience the hard way here, repeatedly proven, anyone that you feel "like lack of commitment from him could possibly influence our culture in a negative way", just pass (at least until you have product market fit or a repeatable business running). As soon as shit hits the fan, they will either leave or drop performance, and you will have to let them go.<p>In your case, I think the issue is not about part time, but the commitment itself. If it's your first hire, you need them to be on-board, and contrary to what most people say, have more expectations than people would for a "normal" employee. The truth is, that person is <i>not</i> a normal employee, it's the first hire in a very early stage business. If you treat that hire as a regular employee, you will build expectations and won't be able to live up to it, and it will backfire for both of you 6-8 months down the road. That will hurt your ability to build a core team, and you will have to start from scratch.<p>Do not give up on that, no matter what the popular opinion tells you. Most people are not founders, and you should trust the guts that you have about building your core team.