Rev. Leroy Lesley moved his family to Tampa in 1848, including 23 year old son, John.  He supervised the construction and pastored at the First Methodist Church in Tampa, est. 1849. 

During the Third Seminole War, Lesley, joined his Father, a vet of the 2nd Seminole War, joined the Florida militia as a member of his father, Captain Lesley's Company, the Florida Mounted Volunteers.  as a private but quickly was promoted to lieutenant.

After President Lincoln called for troops to invade and blockade Florida and her sister States in the Southern Confederacy, Lesley formed a company of Tampa Bay men and was elected its Captain.  On September 7, 1862, Lesley was commissioned Major, having lead his men through the early years of the War.

Upon formation of Florida's commissary unit, Munnerlyn's Battalion (Cow Cavalry) Lesley, a cowman or "cracker" returned for Florida to lead Co. B of the Battalion, with instructions round up the free-range Spanish cattle for food for the Army.   He was injured 10 July, 1864 in Florida when he was shot in the left arm.  A monument to this unit exists in Plant City, Florida.

At the end of the war, Tampa resembled a ghost town. The majority of residents had left the city during the war (although a significant number eventually returned), the economic condition was dismal and there was no municipal government.  Lesley returned home like so many other Confederate Veterans to fight an economic war, to rebuild the economy.   Lesley served as Hillsborough Co. Sheriff for two years and built a sawmill that supplied much of the lumber used to re-build Tampa town, which had been shelled during the war.  Yellow fever, reconstruction and an empty city treasury were some of the challenges.  Lesley ran for a mayor on "Charter revocation" platform, and was elected the 12th Mayor of Tampa.   On October 4, 1869, the state legislature responded as expected and revoked the City’s charter. When the news reached Tampa, Lesley and other City officials resigned their positions.  The Hillsborough County government appropriated all City properties and assumed responsibility for providing educational and other principal services to Tampa’s residents.

The 1870 US Census of Hillsborough County census lists his profession as a cattleman.

After resigning, Lesley returned to his business ventures.  In 1872, he sold his lumber mill to raise cattle for the lucrative Cuban market and accumulated a fortune. Lesley was also one of the founders of the First National Bank and the Tampa Electric Company which, in 1887, installed the first electric traffic lights in Tampa. In 1876, Lesley was elected to the State Legislature and was re-elected in 1882 and 1886. He later campaigned and won a seat in the State Senate and was one of the members of the constitutional convention that drafted the present state constitution.

He received a Florida Confederate Veteran's pension #A11996 in Hillsborough County, Florida

John T. Lesley passed away on July 13, 1913 in Tampa and was buried in historic Oaklawn Cemetery.