I think the most accurate (and unsatisfying) answer is "it depends." I think it would be very, very challenging to be part-time in the early days, even if you were to acquire existing franchise businesses. If you are going multi-unit right out of the gate and you have a lot of capital you could be part-time right out of the gate. If you are trying to bootstrap 1 or 2 units into something larger, you will likely need to be full-time for at least the first year. I have 2 Meineke Car Care franchises and am working on developing more while also working part-time in my previous career. It's been a challenge but it's doable.

You could make it a part-time job eventually, but it likely won't be in the beginning, even if you're buying an existing unit(s). You'll likely need multiple units to get to the scale where the cash flow supports dedicated management that can take you out of the day-to-day operations.