He received his first Captain’s commission in the early part of 1755, and was employed by the New Hampshire government in building a fort at the mouth of the Ammonoosuc River and in guarding its Northern and Western frontiers until July, when he was ordered to Albany to join the army of Major General Johnson.  His first service there was in furnishing escort, with a company of one hundred men, to a provision train from Albany to Fort Edward.  From this latter point he was afterwards repeatedly despatched, with smaller bodies of men, up the Hudson River and down Lake George and Lake Champlain to reconnoiter the French forts.  Some of these expeditions extended as far north as Crown Point and were enlivened with sharp skirmishes.  He was absent up the Hudson upon one of these when the French were defeated at the battle of Lake George and Baron Dieskan was made prisoner.

The efficiency of the campaign of the next year (1756), which contemplated the taking of Crown Point, Niagara and Fort Du Quesne, was seriously impaired by the repeated changes of Commander-in-Chief; Major General Shirley being superceded in June by General Abercrombie while he, about a month later, yielded the command to the inefficient Lord Londown.  The only occurrences of particular note during this campaign were the capture of our forts at Oswego by General Montcalm and the formal declarations of war by the two belligents.

Rogers and his men were stationed at Fort William Henry, and made repeated visits to Ticonderoga and Crown Point to ascertain the power of the enemy and to annoy him as they had opportunity.  They went down Lake George, sometimes by land upon its shores, and sometimes by water and in boats.  In the winter their land marches were frequently upon snow-shoes, and their boats were exchanged for skates.  On such occasions each Ranger was generally his own commissary and carried his own supplies.

In his journal for this year (1756) Rogers notes thirteen of these expeditions as worthy of record.  The first was down Lake George on the ice, in January, with seventeen men, resulting in the capture of two prisoners and two sledges laden with provisions.

The second was made in February with a party of fifty men to ascertain the strength and operations of the French at Crown Point.  Having captured one prisoner at a little village near by the fort, they were discovered and obliged to retire before the sallying troops of the garrison.  With very marked sang froid he closes his account of this reconnoissance by saying:  “We employed ourselves while we dared stay in setting fire to the houses and barns in the village, with which were consumed large quantities of wheat, and other grain; we also killed about fifty cattle and then retired, leaving the whole village in flames.”

There often appears a ludicrous kind of honesty in the simple narratives of this journal.  He occasionally seized certain stores of the enemy which a Ranger could destroy only with regret.  He naively remarks, in narrating the capture in June, of this same year, of two lighters upon Lake Champlain, manned by twelve men, four of whom they killed:  “We sunk and destroyed their vessels and cargoes, which consisted chiefly of wheat and flour, wine, and brandy; some few casks of the latter we carefully concealed.”