It marks the first time anyone infected with incurable Ebola, considered one of the world's deadliest diseases, has been brought into the country.
A second American aid worker infected with the virus was expected to arrive at the hospital within a couple days. US officials are confident the patients can be treated without putting the public in danger.
US-based Samaritan's Purse missionary group, which paid for the transport, told The Associated Press that Dr Kent Brantly is the patient.
An ambulance from Atlanta's Grady Memorial Hospital left the base in Marietta, Georgia, shortly after the Gulfstream landed and drove the 15 miles or so toward Emory University Hospital where Brantly and another aid worker will be treated.
More From This Section
The ambulance with red markings was under light security, flanked by a few SUVs and a police car for the short trip to the hospital along a wide-open Interstate with no traffic.
The second patient, Nancy Writebol, will be brought from Africa soon, the hospital has said. The two seriously ill Americans worked for North Carolina-based Samaritan's Purse and US-based SIM at a Liberian hospital that treated Ebola patients.
Dr Jay Varkey, an infectious disease specialist at Emory who will be involved in Brantly's care, said the hospital's isolation unit is well-equipped to handle patients with diseases that are even more infectious than Ebola.