“Because you lead by example, your companions gain benefits from your methods of exploration. If you're concentrating on keeping a follower with you for the foreseeable future, it's well worth augmenting them as much as possible, though this always comes at the expense of spending points purely on yourself. But that's selfish.”— Fallout 4 Vault Dweller's Survival Guide description
In order for the perk to work, it checks if the number of teammates is greater than 0 and will therefore not work if the player is on a team by themselves.
Fallout: The Roleplaying Game
“Because you lead by example, the maximum number of AP the group may save is increased by 1.”— Fallout 2d20 sourcebook p. 66
Fallout: The Board Game
Once obtained, it can be discarded to take a single companion from another player character or from the shop. It will also unexhaust all companions in the player character's inventory, ignoring their requirements.