Gaidan was born in Nîmes to a wealthy family that owned a bank, Banque Gaidan.

Not having needed to produce abundantly, he quietly painted landscapes of Provence, notably in Nîmes, Toulon, Hyères and Carqueiranne, where he owned the "Villa des Agaves".

Louis Gaidan studied under Charles François Jalabert and Paulin André Bertrand. He painted mainly the shores and inlets of the Mediterranean coast. He adopted the technique of Cézanne, with whom he became friends.

From 1887 to 1903 he exhibited at the Salon des Artistes Français, of which he became a member in 1889, and at the Salon de Nîmes, the Salon de Toulon, the Salon d’Hyères and the Salon de Monaco.

Louis Gaidan was a much-loved painter, known for his light-filled landscapes depicting the south of France, his native country. Like Henri Martin, his moderate pointillism is very harmonious.