First job off the farm which had been tobacco, and tomatoes, and my Great Uncle had cattle and sheep, so lots of hay bales stacked was at 14. I had to get a work permit in MD.
Actually two jobs, one building seawalls and piers, including being a deckhand on a pile driver, driving seawall sheeting with a 110lb sheeting hammer, and all the associated odd labor that went with all that. Paid $2.65/hour.
The other was as a volunteer fireman, mostly getting trained and learning (although that never quit). At 14 we were not supposed to run calls, but we did even though we were relegated to 'outside' duties on structural fires, we were in the thick of it for brush fires and accidents where sometimes the extra manpower made a difference. By the end of my first summer building seawalls, I had a 34 inch waist, stood close to 6 foot, and weighed 240 lbs (a lot of muscle).
In the meantime I held a commercial crabbers (fishing) license, so I could supplement my income selling soft crabs to local restaurants for $3/dozen, which was pretty good money then.