I want to start a company, but I'm worried about the potential legal/ethical fallout from what I have done. I've kept a low profile so far, but obviously if I start a company I will need do a lot of networking, and people will need to know my background. If my work history is publicly known, there is some risk of litigation from the massive-cap companies that I have worked for.
I don't feel I've done anything ethically wrong. I work 80hrs most weeks, and received feedback and promotions from each of the companies. I have never breached any NDA or employment agreement, except for the obligatory clause in most salaried contracts: "don't engage in any other employment, not even as a cashier at Taco Bell". That said, it is a legal grey-area, and a well-funded lawsuit could drag on for a long time.
The company I want to start would be creating a software product which plugs into, or perhaps replaces one of the products I currently work on (it's a very old piece of software). I don't believe this would breach any contracts, since other competitors were born out of similar circumstances (minus the overemployment)
I wanted to get some other perspectives on my situation. Is it salvageable? Or did I ruin my chances by having a non-conventional work history?
If they felt like making an example of a person, they could (and likely would) litigate you into the ground. I honestly don't know if your present/past employers would or wouldn't do that, but it's a nontrivial risk and if it occurred you would be in one heck of a tough spot.
I'm not sure what I'd do, tbh. Without a really good story ("My relative had an exotic disease named after her and I needed to raise cash for an experimental treatment only available in Gstaad during a full moon."), you not just risk legal action, but also risk leaving a bad taste in someone important's mouth ("Will hashxyz two-time me/my investment, as well?").
Is it possible to find someone else to be the point person, while you hang back for the initial phase(s)? If it comes out after you've already got momentum, things may turn out alright. However, as you know, it's a dice roll.
Should ending your employment be a big deal, perhaps better arrangements are possible.
You need to evaluate what is worth what.
Once you have done that, you then need to get them to work through the same questions.
Put them in a position where they get what they want / need for you, the difference being what that costs.
Compensation can take many forms, and greater work freedom is one of them you really want right now.
You might be totally prohibited from starting your own company. You might have signed a contract stating you employer owns all the work you do even outside of work hours. You might be allowed to create your own company as long as it's not competing with your employer or they might require you to disclose it to them.
Point being, look at your contracts. If you have an employer that would be a problem, quit that job. You're going to need to quit at least one of those jobs to have time to start your own company.
As an aside, don't work 80 hours a week forever. It's not healthy. Don't forget to enjoy your life.
IANAL, so I could be totally wrong, but this does not seem grey at all. You broke a contract. The question would be about consequences, not the contract.
The much bigger problem that will keep you away at night is how to get actual paying customers.