He was born in San Salvatore Monferrato, province of Alessandria, on December 16, 1885, the son of Giovanni Ollearo and Carolina Coggiola.

He then participated in the First World War with the 1st Special Mountain Artillery Group, earning a second Silver Medal for Military Valor in 1918.

The "Sforzesca" participated in the subsequent bitter defensive fighting, which managed to halt the Greek offensive by late February.

For the merits achieved on the Albanian front, on 15 November 1941 Ollearo was awarded the title of Officer of the Military Order of Savoy.

[13][14][15][16][17][18][19] From 31 December 1943 to 25 June 1944 he held the position of Undersecretary of the National Republican Army, organizing its headquarters in Rome, with Colonel Vittorio Nebbia as Chief of Staff.