[1][2] Grillo was a widow who also part of the Third Order of Saint Francis; she entered the religious life following the death of her husband.

[1][2] Grillo founded a religious congregation that would expand into Latin America and she would also maintain contact with important individuals such as Luigi Orione and Clelia Merloni both of whom she befriended.

It was there that Grillo graduated in 1873 before she returned to Alessandria where she married Captain Giovanni Battista Michel on 2 August 1877 (the couple did not have children).

[1][2] The couple later moved to Portici and their final relocation was to Naples where her husband died during a parade on 13 June 1891 due to sunstroke.

Her husband's sudden death caused her to sink into a deep depression that made her ill but it was her priest cousin Prelli who guided her through it.

It was around this point that while reading into the life of Giuseppe Benedetto Cottolengo she experienced a sudden conversion in which she resolved to do whatever she could in order to aid the poor.

Grillo sold this house despite the opposition of her relations and instead purchased an old building that she remodeled and renamed as the Little Shelter of Divine Providence.

These women helped become the basis for the religious congregation that Grillo founded on 8 January 1899 with the permission of the Bishop of Alessandria Giuseppe Capecci (she had written her order's first Rule in 1898).

Grillo later entered the Third Order of Saint Francis on 14 January 1893 and around that time donated her wedding garment to the Capuchin church in Alessandria to be used as a sacred vestment.

The postulation later submitted the official Positio dossier in 1981 which was an accumulation of all documentation and witness interrogatories in relation to Grillo's life and reputation for holiness.