Dr Kent Bradley has arrived at a hospital in Atlanta where he's to be treated in an isolation unit.
He was helped by another medic as he walked from an ambulance into hospital in a head to toe protective suit.
He was serving in west Africa with the Christian charity Samaritan's Purse.
Another missionary from the charity, who's also suffering from the disease, is expected to be transported back to the US within the next few days.
President Franklin Graham said: "We thank God that they are alive and now have access to the best care in the world.
"We are extremely thankful for the help we have received from the State Department, the CDC, the National Institute of Health, WHO and, of course, Emory Hospital."
Samaritan's Purse says it is working to evacuate all but the most essential personnel to their home countries.
This Ebola virus has claimed the lives of over 700 people since it was first reported in Guinea back in February.
It's led to concerns it could be brought into the UK.
The death rate for this virus stands at around 55% and although medics can treat the symptoms, it is incurable.