Upon his return to Spain in 1787, he was attached to the Flandres Regimiento, with the rank of Infantry Colonel, and was received in the Order of Malta.

Because the local indigenous population working in the indigo industry had declined greatly, Carondolet recruited Spanish laborers.

He made many improvements in the infrastructure of New Orleans, including the Carondelet Canal and the city's first street lighting.

The street light tenders (attendants) served as watchmen and de facto municipal police.

He wanted to thwart the American policy of trying to secure unchallenged access to the Mississippi River, a goal which made Spanish colonial officials fear for the independence of Louisiana and New Spain.

He commissioned 29 free men of color in the militia and was proud of the three companies he formed with soldiers of African descent.

[3] After his term in Louisiana, Carondelet served as President of the Real Audiencia de Quito from 1799 through his death in 1807, supervising territory including present-day Ecuador, parts of Peru and Colombia.