Sarrut was born on 16 August 1765 at Canté in what is now the department of Ariège, France, which is on the border with Spain. He became Chef de Brigade (colonel) of the 3rd Demi-Brigade de bataille on 28 May 1794. He transferred to command of the 8th Infantry Demi-Brigade on 19 February 1796. That year the 8th was serving with the Army of the North, but in 1797 the unit transferred to the Army of Germany. In 1798, the demi-brigade switched between the Army of Mainz, the Army of the Danube, and the Army of the Rhine. At the Battle of Hohenlinden on 3 December 1800, the 8th Demi-Brigade with a strength of 2,680 men was part of Antoine Richepanse's division.