Born on 16 March 1759 in Saint-Fortunat-sur-Eyrieux in Ardèche department, Rampon joined the French royal army in 1775.

During the Montenotte Campaign he gained fame by his gallant defense of Monte Negino (or Legino) on 11 April 1796, where his soldiers repelled the attacks of a superior Austrian force.

While in André Masséna's division, Rampon played a major role at the battles of Lonato and Castiglione in August.

He was described by Louis Desaix as, "square figure ... not a thief, big, leans backward; very dark skin".

[6] After fighting in Switzerland under Guillaume Brune in 1798, where he Forced the crossing of Gümmenen, he joined Bonaparte's Egyptian expedition.

In 1814 he held the fortress of Gorinchem (Gorkum) in the present-day Netherlands until 7 February, when he was compelled to surrender to the Prussians.

Rampon rallied to Napoleon during the Hundred Days and thereafter the Bourbons held him in ill-favor until 1819 when his noble title was restored.