US President, Lyndon B. Johnson ("LBJ") was the first ever US President to visit Australia. LBJ made two visits to Australia in 1966 and 1967.
The first visit took place between 20th and 23rd October 1966 when he visited Canberra, Melbourne, Sydney, Brisbane, and Townsville. There were significant Vietnam war protests during this visit as seen in this newsreel.
President, Johnson visited a second time on 21st and 22nd December 1967 when he attended the funeral of Prime Minister Harold Holt (who drowned while swimming off the coast of Victoria).