While fighting in the Peninsular War, he led a brigade at Bussaco and a division at Fuentes de Oñoro and Salamanca.

He joined the Constitutional Guard of Louis XVI on 9 December 1791 and rapidly became a brigadier, then a maréchal des logis.

After the Constitutional Guard disbanded on 30 May 1792, he was briefly a sous-lieutenant in the King's Regiment before he was elected adjutant major in the 9th Battalion of the Haute-Saône Volunteers.

For his efforts, Jean Baptiste Camille Canclaux and Jean-Baptiste Kléber promoted Ferey chef de bataillon (major).

[2] In 1800, the 24th Light was assigned, with the 43rd and 96th Line Infantry Regiments to Jacques-Antoine de Chambarlhac's division of Napoleon Bonaparte's Army of Reserve which invaded northern Italy.

[7] As punishment for bad behavior at Montebello, the 24th Light was assigned to screen the army the night before Marengo was fought, and it endured being bombarded by Austrian artillery.

[1] At the Battle of Austerlitz on 2 December 1805, he led a brigade in Dominique Vandamme's 2nd Division in Marshal Jean-de-Dieu Soult's IV Corps.

[9] At the Battle of Jena-Auerstedt on 14 October 1806, Ferey commanded a brigade in Jean François Leval's 2nd Division in Soult's IV Corps.

[11] Leval's division, including Ferey's brigade, was involved in a minor clash at Bergfried on 3 February 1807.

[13] In the Battle of Lomitten on 5 June 1807, Ferey's brigade was part of Claude Carra Saint-Cyr's division.

[14] At the Battle of Heilsberg on 10 June 1807, Soult's IV Corps suffered 8,286 casualties and Ferey was wounded.

He commanded a brigade in Louis Henri Loison's 3rd Division in Marshal Michel Ney's VI Corps.

The division fought its way up the ridge through the Allied skirmishers in two main attack columns, with Ferey's brigade on the left.

As the French neared the crest, they were surprised when British infantry appeared and fired a volley from very close range, routing them.

At this point, Ferey's division was no longer battleworthy and, for the rest of the day, Jean-Baptiste Drouet's IX Corps bore the burden of fighting in the village.

[25] At the Battle of Salamanca on 22 July 1812, Ferey commanded the 3rd Division of Marshal Auguste de Marmont's Army of Portugal.

Clausel sent Jacques Thomas Sarrut's division to assist his mauled left flank and tried to exploit the success in the center.

Historian Charles Oman wrote that Ferey, "carried it out with splendid courage, and by his constancy gave time for the escape of the whole of the confused mass behind him."

[28] A different Claude François Ferey, born on 22 December 1723, attained the rank of general of brigade on 25 August 1793, and died on 6 January 1806.