One aspect of the game that adds greatly to its popularity are the generic geomorphic mapboards, each of which can be aligned to any edge of the same length to any other mapboard (except river boards). Most scenarios give each player, generally speaking, enough simulated men to make up a company, though order of battle is not precise and most scenarios only give a flavor of what the real life battles were like rather than a direct simulation. Leaders can exert a favorable influence on the firing of support weapons, or the morale rolls of squads with whom they are stacked, although if a leader fails a morale check the squads stacked with him must check for morale a second time. The squad leaders in Squad Leader are actually 'factored in' to the squad counters, and only exceptional leaders - officers and NCOs - are portrayed separately, by their own counters. The name of the game is actually a misnomer, as in most ways the player assumes the role of a company commander (i.e. Advance phase (in which the player whose turn it is may move every unit one hex), and the close combat phase (in which any units from opposite sides that start that phase in the same hex engage in close combat).Rout phase (in which any 'broken' units must flee for cover).Advancing fire phase (in which any units that moved may fire, at reduced strength).Defensive fire phase (in which the other player may fire on units that just moved).Movement phase (in which the player may move their units on the board).Prep fire phase (in which the player whose turn it is may fire on enemy units any units that prep fire cannot move or fire again for the rest of the player's turn).

Rally phase (in which 'broken' units attempt to rally and malfunctioning weapons are repaired).Each turn consists of two player turns, each of which have eight 'phases': The semi-simultaneous system of play developed in the mid-1970s can be seen in Squad Leader's sequence of play. Time was said to be two minutes per turn, though the developer admits that this is also inexact and that each game turn should be considered a 'module of time, such that the (game's) events can occur and interact with one another.' In reality, European village streets are not 40 meters across, for example. The mapboards are divided into hexagonal grids with each hex said to represent 40 metres of terrain, the result of the designer being asked what the ground scale was, rolling a die and it coming up 'four'. British troops, when eventually added to the game system, are shown as largely similar to the Germans, albeit with somewhat inferior equipment. US troops are shown as having unusually high firepower (representing larger squads, using the Browning Automatic Rifle - unlike other nationalities who have separate counters for light machine guns), but with slightly lower base morale than German or Soviet troops, representing the supposed greater tendency of more individualistic Americans to break from their orders or the group under fire - however, American troops are easier to rally under fire, as they were exempt from the usual penalty ('desperation morale') paid by broken squads in these circumstances. Russian troops are portrayed as poorly armed (and with poor quality radios, making it very difficult for them to summon artillery support) and with relatively fewer leaders, but with the capacity to become 'berserk' in combat (a capacity shared in later expansions by SS troops).

The original game contains counters representing the German, Russian and American armies.

Pieces in Squad Leader represent regular squads (rated for firepower, range and morale), weapon and vehicle crews, elite squads (with high firepower and morale but shorter range - used to represent paratroops or combat engineers armed with sub-machine guns), individual leaders, support weapons, and vehicles.

Squad leader