I'm sort of an accidental driver. I went to work for a towing company, and the CDL drivers both up and quit. So I got my Class A, and worked there for about a year after, and then ended up quitting to take a job in my field (agriculture). 5 years later a friend of mine bought a truck, and asked me to team with him. I got a new medical card, and having been out of the truck for 5 years (and no tractor trailer experience at all) drove for a few months team, then for a couple years solo, and now we're doing some more team stuff. I've pulled flatbed, dry van, and reefer, all for the same o/o, sometimes all 3 in a week.
I seem to be in the minority however, as I didn't go to school, didn't work for a big otr outfit, and am a "part time" otr driver. (I go out for two weeks or so, then home for 2-4 weeks, then another 2 weeks on the road. Typically for about half the year. The rest of the time I have a consulting business in another field)
I'm curious about how others got started, and how this industry has worked for you. Though I don't do it full time, I can honestly say that trucking has allowed me a much higher standard of living than I would have had otherwise, and I'm grateful for the opportunity.