Basically, he was a “gentleman scientist.” His father was a wealthy doctor and businessman who set him up for life. His research was mostly self-funded. he was officially listed as an unpaid “Captain’s Companion” and a “Naturalist” on the Beagle, but he never actually punched a clock for anybody. He was independently well-heeled.
Perhaps it should be mentioned that it was once not unusual for science to be a “hobby,” of sorts for rich people, rather than a paid profession.