Sukarno as an HBSstudent in Surabaya, 1916

The son of a Javanese primary school teacher, an aristocrat named Raden Soekemi Sosrodihardjo, and his Hindu Balinese wife from the Brahmin varna named Ida Ayu Nyoman Rai from Buleleng regency, Sukarno was born at Jalan Pandean IV/40, Soerabaia (now known as Surabaya), East Java, in the Dutch East Indies (now Indonesia).^[7][8] He was originally named Kusno Sosrodiharjo^[9] Javanese pronunciation: [kʊsnɔ]. Following Javanese custom, he was renamed after surviving a childhood illness. After graduating from a native primary school in 1912, he was sent to the Europeesche Lagere School (a Dutch primary school) in Mojokerto. Subsequently, in 1916, Sukarno went to a Hogere Burgerschool (a Dutch type higher level secondary school) in Surabaya, where he met Tjokroaminoto, a nationalist and founder of Sarekat Islam. In 1920, Sukarno married Tjokroaminoto's daughter Siti Oetari. In 1921, he began to study civil engineering (with focusing on architecture) at the Technische Hoogeschool te Bandoeng (Bandoeng Institute of Technology), where he obtained an Ingenieur degree (abbreviated as "Ir.", a Dutch type engineer's degree) in 1926. During his study in Bandung, Sukarno became romantically involved with Inggit Garnasih, the wife of Sanoesi, the owner of the boarding house where he lived as a student. Inggit was 13 years older than Sukarno. In March 1923, Sukarno divorced Siti Oetari to marry Inggit (who also divorced her husband Sanoesi). Sukarno later divorced Inggit and married Fatmawati.

After graduation in 1926, Sukarno and his university friend Anwari established the architectural firm Sukarno & Anwari in Bandung, which provided planning and contractor services. Among Sukarno's architectural works are the renovated building of the Preanger Hotel (1929), where he acted as assistant to famous Dutch architect Charles Prosper Wolff Schoemaker. Sukarno also designed many private houses on today's Jalan Gatot Subroto, Jalan Palasari, and Jalan Dewi Sartika in Bandung. Later on, as president, Sukarno remained engaged in architecture, designing the Proclamation Monument and adjacent Gedung Pola in Jakarta; the Youth Monument (Tugu Muda) in Semarang; the Alun-alun Monument in Malang; the Heroes' Monument in Surabaya; and also the new city of Palangkaraya in Central Kalimantan.

Atypically even among the country's small educated elite, Sukarno was fluent in several languages. In addition to the Javanese language of his childhood, he was a master of Sundanese, Balinese and of Indonesian, and was especially strong in Dutch. He was also quite comfortable in German, English, French, Arabic, and Japanese, all of which were taught at his HBS. He was helped by his photographic memory and precocious mind.^[10]

In his studies, Sukarno was "intensely modern," both in architecture and in politics. He despised both the traditional Javanese feudalism, which he considered "backward" and to blame for the fall of the country under Dutch occupation and exploitation, and the imperialism practised by Western countries, which he termed as "exploitation of humans by other humans" (exploitation de l'homme par l'homme). He blamed this for the deep poverty and low levels of education of Indonesian people under the Dutch. To promote nationalistic pride amongst Indonesians, Sukarno interpreted these ideas in his dress, in his urban planning for the capital (eventually Jakarta), and in his socialist politics, though he did not extend his taste for modern art to pop music; he had Koes Bersaudara imprisoned for their allegedly decadent lyrics despite his own reputation for womanising. For Sukarno, modernity was blind to race, neat and elegant in style, and anti-imperialist.^[11]