The strategy of the Roman military contains its grand strategy (the arrangements made by the state to implement its political goals through a selection of military goals, a process of diplomacy backed by threat of military action, and a dedication to the military of part of its production and resources), operational strategy (the coordination and combination of the military forces and their tactics for the goals of an overarching strategy) and, on a small scale, its military tactics (methods for military engagement in order to defeat the enemy). If a fourth rung of "engagement" is added, then the whole can be seen as a ladder, with each level from the foot upwards representing a decreasing concentration on military engagement. Whereas the purest form of tactics or engagement are those free of political imperative, the purest form of political policy does not involve military engagement. Strategy as a whole is the connection between political policy and the use of force to achieve it.

In its clearest form, strategy deals solely with military issues: either a threat or an opportunity is recognised, an evaluation is made, and a military stratagem for meeting it is devised. However, as Clausewitz stated, a successful military strategy may be a means to an end, but it is not an end in itself. Where a state has a long term political goal to which it applies military methods and the resources of the state, that state can be said to have a grand strategy. To an extent, all states will have a grand strategy to a certain degree even if it is simply determining which forces to raise as a military, or how to arm them. Whilst early Rome did raise and arm troops, they tended to raise them annually in response to the specific demands of the state during that year. Such a reactive policy, whilst possibly more efficient than the maintenance of a standing army, does not indicate the close ties between long-term political goals and military organization demanded by grand strategy.

Early indications for a Roman grand strategy emerged during the Punic Wars with Carthage, in which Rome was able to influence the course of the war by selecting to ignore the armies of Hannibal threatening its homeland and to invade Africa instead in order to dictate the primary theater of war.

In the Empire, as the need for and size of the professional army grew, the possibility arose for the expansion of the concept of a grand strategy to encompass the management of the resources of the entire Roman state in the conduct of warfare: great consideration was given in the Empire to diplomacy and the use of the military to achieve political goals, both through warfare and also as a deterrent. The contribution of actual (rather than potential) military force to strategy was largely reduced to operational strategy – the planning and control of large military units. Rome's grand strategy incorporated diplomacy through which Rome might forge alliances or pressure another nation into compliance, as well as the management of the post-war peace.

Vegetius once wrote that "every plan... is to be considered, every expedient tried and every method taken before matters are brought to this last extremity [general engagements]... Good officers decline general engagements where the odds are too great, and prefer the employment of stratagem and finesse to destroy the enemy as much as possible... without exposing their own forces.". However, Vegetius was writing late in the fourth century AD, in the latter years of the Empire. During this period, and for much of the Empire, it can be argued that the Romans did follow a grand strategy calling for limited direct operational engagement. However, earlier in its history, in the Republic and early Empire Rome showed little reluctance to become engaged in direct military engagement, prosecuting offensive operations against numerous adversaries.

When a campaign did go badly wrong, operational strategy varied greatly as the circumstances dictated, from naval actions to sieges, assaults of fortified positions and open battle. However, the preponderance of Roman campaigns exhibit a preference for direct engagement in open battle and, where necessary, the overcoming of fortified positions via military engineering. The Roman army was adept at building fortified camps for protection from enemy attack, but history shows a reluctance to sit in the camp awaiting battle and a history of seeking open battle.

Roman armies of the Republic and early empire worked from a set tactical 'handbook', a military tradition of deploying forces that provided for few variations and was ignored or elaborated only on occasion.

Once the legion had deployed on an operation, they would generally march to their objective. There were exceptions when the armies were transported by the Roman navy but even then in most instances this was followed by a march of several days or weeks. The approach to the battlefield was made in several columns, enhancing maneuver. Typically a strong vanguard preceded the main body, and included scouts, cavalry and light troops. A tribune or other officer often accompanied the vanguard to survey the terrain for possible camp locations. Flank and recon elements were also deployed to provide the usual covering security. Behind the vanguard came the main body of heavy infantry. Each legion marched as a distinct formation and was accompanied by its own baggage train.