Alexander Ollongren was born on November 9, 1928, on a coffee plantation in Kepahiang, in the southwestern part of Sumatra, Netherlands East Indies.

The family moved to Java in early 1932 and lived in Yogyakarta, while the Japanese army occupied the Netherlands East Indies in 1942.

The family stayed in Australia for six months in order to recuperate and later moved to the Netherlands where Ollongren decided to enroll in Leiden University.

His education at Leiden University started with undergraduate and graduate studies in mathematics, Hamiltonian mechanics, physics, and astronomy, after which he gained his MSc degree in 1955.

In 1958, he started his doctoral research in galactic astronomy, supervised by Jan H. Oort and Hendrik C. van de Hulst of the Astronomical Department at Leiden.

The analysis of the problem, together with the computational results and Ollongren's interpretation of them, earned him a PhD degree in astronomy from Leiden University in 1962.

A modern, transistorized computer, the X1, built by the Dutch company Electrologica, was installed and Ollongren was appointed Acting Director of the Institute.

[citation needed] After his retirement, he became interested in the academic debate on the Search for ExtraTerrestrial Intelligence (SETI), within the International Astronautical Academy.