He was actively involved in the development of political awareness in Portuguese Timor, which caused him to be exiled for two years in 1970–71 to Portuguese East Africa.
Horta sangat aktif terlibat dalam pengembangan kesadaran berpolitik di Timor Portugis yang menyebabkannya diasingkan selama dua tahun pada 1970-1971 ke Afrika Timur Portugis.