The Continental Congress appointed Nicholas Haussegger to command the battalion, which initially organized in the strength of eight companies.

A week later, the German Battalion was in action at Assunpink Creek where a number of its troops were captured, including Haussegger.

After Haussegger defected to the British, George Washington appointed the Prussian volunteer Henry Leonard d'Arendt to command the battalion.

On 17 July the ninth company was recruited from Pennsylvanians at the urging of George Washington as a way to employ French and Indian War veteran Lieutenant John David Woelper of the 3rd Pennsylvania Battalion.

[3] A Bernese Swiss veteran of the French and Indian War who settled in Lebanon, Pennsylvania,[4] Haussegger was promoted on 17 July 1776.

Together with the 254-man 1st Continental Regiment of Edward Hand, the battalion served in Matthias Alexis Roche de Fermoy's brigade.

[7] Early in the combat, Washington moved Fermoy's brigade to the east to prevent the Hessian defenders from retreating north to Princeton, New Jersey.

[10] As New Years Day 1777 dawned, a reinforced American brigade took position behind a creek 6 miles (10 km) south of Princeton, New Jersey, ready to block the advance of Lord Charles Cornwallis' forces.

Among the 1,000 Americans were Hand's riflemen, now called the 1st Pennsylvania Regiment, Charles Scott's Virginia Brigade, the German Battalion, and six artillery pieces under Thomas Forrest.

[12] The next day, Cornwallis brought on the Battle of the Assunpink Creek when he launched a major push with 8,000 troops and 28 guns.

As dusk fell, superior British numbers forced Hand's troops into a hurried retreat through the town.

[15] That evening, columns of British and Hessians tried to storm the bridge and the lower fords, but were stopped with heavy losses.

[15] Under the command of Lieutenant Colonel Stricker, the battalion fought in the Battle of Spanktown on 23 February 1777 during the Forage War.

[18] By this time, the German Battalion shed its status as an Extra Regiment and was counted as part of two state establishments.

On 9 April, two additional majors were added as Daniel Burchardt and George Hubley joined William Klein in that rank.

[15] At the Battle of Brandywine on 11 September 1777, Muhlenberg's brigade formed part of Nathanael Greene's division near Chadds Ford.

[25] After Sir William Howe's heavy column reached a position in the American right rear, Washington sent the divisions of John Sullivan, Stephen, and Lord Stirling to block the thrust.

[27] South of Dilworth, the 2nd Grenadier Battalion ran into Weedon's brigade and other troops and its commander Henry Monckton had to call for assistance.

[32] Francis B. Heitman showed the 6th Virginia Regiment in Muhlenberg's brigade at Valley Forge, along with the German Battalion and the previously listed units.

[3] Henry Dearborn's journal listed the "German Regt" under Weltner in Hand's Brigade, together with Lieutenant Colonel Adam Hubley's 11th Pennsylvania Regiment and independent companies led by Captains John Paul Schott and Simon Spaulding.