The Cephissus river flows through the industrialized eastern part of the municipality; about 1/4 of its area is taken up by factory developments.

Cleisthenes, the Athenian statesman and lawgiver credited with creating the constitution that gave birth to the democratic regime of ancient Athens, was born in Aigaleo.

According to Herodotus, it was from the top of Mount Aigaleo that, in 480BC, Xerxes observed the Battle of Salamis and the destruction of the Persian fleet.

In 1874, the gunpowder factory "Ελληνικόν Πυριτιδοποιείο"/Ellinikon Pyritidopoieio was built, transforming Aigaleo into a heavily industrial area, covered by thick smog.

With the ability to produce more than 60.000 bullets per day, including heavy weapon shells, it became the primary supplier of the Greek army.

After the fall of Smyrna in 1922 during the Greco-Turkish war, Aigaleo's population greatly increased due to the settlement of mostly Greek refugees from Asia Minor and Pontus, but also of Assyrians.

[4] On September 29, 1944, during the Axis occupation of Greece, a massacre of at least 65 civilians (with estimates ranging up to 150 casualties[5]) by the German forces took place in Aigaleo's Agios Georgios neighborhood.

Aigaleo was always known for its nightlife, with numerous night clubs and bouzoukia, playing mostly Greek folk tupes of music such as Laïko and Rebetiko.

Some of the greatest music artists of all time have lived and performed in Aigaleo, such as Giorgos Zampetas, Stelios Kazantzidis and Marinella.

The town also operates the cultural centre "Elliniko Molybi"(the Greek pencil), that promotes local young artists, also teaching literature and theatre writing.