It appears that a settlement already existed, likely to oversee the road leading to Acqui Terme. The first reliable historical documents confirming its existence date back to 967 and refer to the donation of Monferrato territories by Otto I to Aleramo, founder of the Aleramici dynasty and patriarch of the region. Soon after, Gamalero came under the Diocese of Acqui, where it remained until 1405.
The village never held significant strategic or political importance, so historical records are sparse, largely following the fortunes of Alessandria until 1707, when Gamalero became part of the Savoy state. The village once had a castle, as evidenced by the municipal coat of arms and a description dating to 1461. It was likely a fortress with three towers, though no traces of it remain today.
Among the notable religious buildings, the parish church of San Rocco, built in 1750 in brick with a Neoclassical appearance, features a frescoed interior. The Oratory of San Sebastiano and the Holy Trinity, constructed on the site of an original pieve in 1665 and home to the confraternity of the Holy Trinity, was externally restored in 1980. Inside, it houses interesting objects used for religious services and processions, and its ceiling is frescoed. The Baroque altar, carved in wood, is particularly striking.
Finally, the church of San Lorenzo, built in 1515 to expand the existing Church of Santa Maria due to population growth, saw its façade reconstructed in 1767 in the Baroque style. Made of brick, it is decorated with pilasters and topped by a statue. The interior is Baroque as well, with frescoes on the ceiling and pillars, whose capitals are adorned with gilded stuccoes.

It appears that a settlement already existed, likely to oversee the road leading to Acqui Terme. The first reliable historical documents confirming its existence date back to 967 and refer to the donation of Monferrato territories by Otto I to Aleramo, founder of the Aleramici dynasty and patriarch of the region. Soon after, Gamalero came under the Diocese of Acqui, where it remained until 1405.

The village never held significant strategic or political importance, so historical records are sparse, largely following the fortunes of Alessandria until 1707, when Gamalero became part of the Savoy state. The village once had a castle, as evidenced by the municipal coat of arms and a description dating to 1461. It was likely a fortress with three towers, though no traces of it remain today.

Among the notable religious buildings, the parish church of San Rocco, built in 1750 in brick with a Neoclassical appearance, features a frescoed interior. The Oratory of San Sebastiano and the Holy Trinity, constructed on the site of an original pieve in 1665 and home to the confraternity of the Holy Trinity, was externally restored in 1980. Inside, it houses interesting objects used for religious services and processions, and its ceiling is frescoed. The Baroque altar, carved in wood, is particularly striking.
Finally, the church of San Lorenzo, built in 1515 to expand the existing Church of Santa Maria due to population growth, saw its façade reconstructed in 1767 in the Baroque style. Made of brick, it is decorated with pilasters and topped by a statue. The interior is Baroque as well, with frescoes on the ceiling and pillars, whose capitals are adorned with gilded stuccoes.