Niko Gjivović - Johnson started his career in Rijeka as an assistant to his uncle Mate, who was also a dentist, and then studied dental surgery in the USA.
After he returned to Rijeka, he again worked with his uncle and as a dentist at the Military - Naval Academy. He moved again, this time to England, and then to Split (1904-1919 intermittently). In Split, he was one of the forerunners in passing on American and English dental treatment experiences.
Not only was he a distinguished professional, but also a pioneer in cycling, motorcycling and one of the first motorists. He was also a ship modeler and steam and electric machines modeler.