Lars Strömbäck assumes in his short biography that as a boy he was apprenticed to a local builder.
[1] Records from 1826 mention Jonsson as foreman ("verkmästare) at the building of the empire style church at Lofta on Öland which was designed by the prominent architect Axel Nyström (1793–1868).
This took place at a time when the Empire style was popular throughout Europe; particular so in Sweden where it had been introduced by King Karl Johan of Sweden (former Marshal of France General Bernadotte), where it was named the "Karl Johan Empire style".
This fashion was sustained by France paying some of its debts to Sweden in ormolu bronzes rather than in currency.
He was so successful as a lighthouse-builder that he was eventually offered such jobs without the standard tender procedure for government-financed buildings.