From 1848 to 1860, Cooley acquired several properties in the Tampa region, including one at Worth's Harbor. By 1850, he lived with seven slaves and was a Captain of the "Silver Grays"—a militia for the home defense of Tampa in the 1850s. He owned a general store in the city, eventually sold to a member of the Tampa Masonic Lodge. He was nominated Port Warden of Tampa in 1853. By 1855, Cooley had become a leader in local politics; he was the chairman at a meeting of the Democratic Party in Tampa, with members enrolled, on August 4, 1855. He was brought in as an alternate councilman for two months in the first Tampa council, served a full-year term beginning in February 1857, and returned in 1861 for another full term. Cooley estimated his personal wealth at $10,060 in 1860.