Kalb was schooled at Kriegenbronn and left home at age 16.
Despite humble origins, he became a military officer, a French Army veteran with service under maréchal de Saxe, and a protégé of the militarily influential Broglie family.
He first traveled to North America in 1768 to assess the growing Anglo‐American split, and with the outbreak of war returned to seek a command in the Continental army. Kalb's skill and credentials, coupled with the Marquis de Lafayette's influence and devotion to the Revolution's principles, overcame Congress's suspicion of foreign adventurers and earned a major general's commission.
Despite the appointment, Kalb found battle elusive.
He reorganized the Southern Department's remaining forces, only to have Congress place Horatio Gates at their head.
From his retirement at Milon la Chapelle, Kalb went to Metz for garrison duty under de Broglie in 1775.
Soon afterwards he received permission to volunteer in the army of the American colonies, in which the rank of major-general was promised to him by Silas Deane.
After many delays he sailed with eleven other officers on the ship fitted out by Lafayette and arrived at Philadelphia in July 1777.
His commission from Deane was disallowed, but the Continental Congress granted him the rank of major-general (dating from the 15th of September 1777), and in October he joined the army, where his growing admiration for Washington soon led him to view with disfavour de Broglie's scheme for putting a European officer in chief command.
In his camp at Buffalo Ford and Deep River, General Horatio Gates joined him on the 25th of July; and next day Gates led the army by the short and desolate road directly towards Camden.
On the nth-13th of August, when Kalb advised an immediate attack on Rawdon, Gates hesitated and then marched to a position on the Salisbury-Charlotte road which he had previously refused to take.
Here in 1825 Lafayette laid the corner-stone of a monument to him.
In 1887 a statue of him by Ephraim Keyser was dedicated in Annapolis, Maryland. See Friedrich Kapp, Leben des amerikanischen Generals Johann Kalb (Stuttgart, 1862; English version, privately printed, New York, 1870), which is summarized in George W. Greene's The German Element in the War of American Independence (New York, 1876).
On 16 August 1780, Kalb led a Continental regiment at the disastrous Battle of Camden, where he received numerous bayonet wounds.
He died three days later.