This ability only works on certain enemies which provide Copy Abilities, and Kirby can only have up to three Friends at a time. If a fourth is claimed, the game will prompt the player to replace one of Kirby's existing friends with the new recruit.
To pull out a heart, the player must press the X button. From there, any enemy that can be charmed will have a small heart icon over their head when Kirby draws near. From there, to charm the enemy, Kirby must toss the heart at the enemy and hit them with it. Kirby can also cause a friend to appear if he hits a Copy Essence or discarded ability with a heart.
When an ally tosses a Friend Heart, that ally will transform into whichever enemy the heart was thrown at, instead of recruiting it as a new ally.
Some Bosses and Mid-Bosses are also recruitable as friends. However, before they can be recruited, they must be defeated in battle. Once they are downed, a heart can be tossed at them. Story Mode bosses like Whispy Woods (only at Fruity Forest), Pon & Con, King Dedede, and Meta Knight can be befriended by throwing hearts at them quickly after defeated. Tossing hearts at the latter two adds them to Kirby's team as Dream Friends.
- When quickly pulling out and tossing a heart, it will automatically be arced toward a friend-able enemy's position if thrown near one.
- When a Friend Heart is tossed at Bomber, Don Puffle, Noddy and Walky, they are instead turned into the hat of their respective Copy Ability - Crash, Festival, Sleep and Mike, respectively.
- When allies are turned into enemies by specific attacks from Morpho Knight and Void Termina's Final Core / Void Soul / Void, Friend Hearts can undo that effect.
- Though throwing a friend heart to most bosses does nothing during battle, throwing it at Void Termina's Final Core / Void Soul / Void damages it slightly.