The move functions as a counterattack, hence the name. When used, the Brawler takes a defensive stance with their hands covering their face, similar to Little Mac when he uses Slip Counter. If not hit, the Brawler goes through a small period of endlag, but if they are hit, a heartbeat line icon will appear above their head, and the Brawler will proceed to grab the opponent and slam them onto the ground behind them, damaging anyone else who might be nearby. Afterwards, the countered opponent will bounce off the ground and be sent reeling, though the distance the opponent flies will depend on how much damage they have taken thus far. In the air, the throw deals knockback at a more vertical angle, and the knockback is reduced slightly, however the higher launch angle can allow for KOs off the upper blast line.
Counter Throw is unique in many ways: it is actually very fast for a counter due to its extremely low ending lag, making it relatively safe if it fails, though this is compensated by the move's very short counter window. It is also tied with Gut Check for having the second highest damage multiplier out of all counterattacks, at 1.5x (only Tetrakarn is higher, at 1.6x), and has the highest knockback growth, allowing it to KO even against weak hits. However, it has multiple flaws: since the counterattack is a grab, the opponent must be within close range to be grabbed; attacks from below soft platforms or moves with a long enough range (most often disjointed hitboxes) will outrange the grab, causing it to miss. Furthermore, it has the least reliable counter detection in the game, not only possessing the shortest window in the game (a mere 18 frames compared to an average of around 23 frames), but also is one of the few counters which requires attacks to strike a certain part of Brawler's body, being their arm or hand. If the incoming hitbox does not overlap with their arm hurtbox the counter will fail and Mii Brawler will be damaged normally, which is most noticeable when attacking from behind or below. Finally, it will always fail against indirect attacks such as projectiles, even if the user is standing directly in front of Mii Brawler.
As a result, Counter Throw is a low-lag option that allows the Brawler to heavily punish enemy mistakes, but is very inconsistent due to its flaws. It can be considered a "high-risk, high-reward" counterattack due to its speed, power, and inconsistency.