Ali was born in Grabag, Purworejo, Dutch East Indies (now Indonesia), to an aristocratic family from Magelang and studied at Leiden University.

After the recognition of the sovereignty of the Republic of Indonesia, he was appointed the first Indonesian Ambassador to the United States, Canada, and Mexico, from 1950 until 1955.

Raden Ali Sastroamidjojo was born in Grabag, Central Java, Dutch East Indies (now Indonesia).

In hoping to find a proper environment for the development of their children, the Sastroamidjojo family moved to the city, where he was sent to receive a European education.

[5][6] He officially began his education when he took Dutch lessons to be accepted in the second class of the Europeesche Lagere School (ELS), but he only lasted a year there due to bullying.

[13] In 1929, Sukarno and other key PNI leaders were arrested on 29 December, by Dutch colonial authorities in a series of raids throughout Java.

[14][10][15] After World War II ended, he continued his activities in politics and government, becoming deputy minister of education in the first Indonesian cabinet.

After the Wilopo Cabinet's fall, following the killing of five peasants near Medan while removing squatters from foreign-owned estate lands, in what became known as the “Tanjung Morawa affair,” Ali was chosen to lead the new cabinet, which was formed after over six weeks of bargaining and five different attempts at various party combinations.

[20] On 25 August 1953, the new prime minister, Ali Sastroamidjojo, announced a 16-month schedule for elections starting from January 1954.

On 4 November 1953, Ali Sastroamidjojo and his cabinet announced the creation of the new Central Electoral Committee ("Panitia Pemilihan Indonesia"), the forerunner to the General Elections Commission.

[21] Under the cabinet, the bureaucracy was expanded with more PNI officials, and the economy was under a period of Indonesianization, with the government encouraging indigenous businessmen to open new firms.

[18] After the recognition of the sovereignty of the Republic of Indonesia, he was appointed the first Indonesian Ambassador to the United States, Canada, and Mexico, from 1950 until 1955.

[22] The Indonesian National Party (PNI), of which Ali was a part, had failed to confront Indonesia's political problems coherently.

Though the party didn't gain mass support, it reflected the wide criticisms against the PNI under Suwiryo's leadership.

[23] In the 9th PNI Congress, held in Surakarta, Central Java, in July 1960, Ali was chosen to head the party, replacing the ineffective Suwiryo.

As head of the PNI, Ali was described as "a consummate politician imbued with a healthy sense of self-preservation", but often disappointed his supporters from the young and left-wing camp by often positioning himself in the middle.

"[25] The working committee of the PNI Congress also agreed that Marhaenism is a form of Marxism "which is applied by the conditions and situation of Indonesia."

[15] Following the failed 30 September Movement coup, led by the Communist Party of Indonesia (PKI), the political winds began to shift.

It was said that General Ali Moertopo was directly involved in the Congress to purge the left wing from the PNI.