Knuckles is a tough, wild, egotistical, and headstrong echidna. Serious and stubborn, Knuckles has no patience for stationary work, like paperwork, and prefers to be where the action is. However, he is an overall nice guy in normal conversations.

Knuckles is fiercely loyal to his homeland and prefers to stay there. As such, when anything bad befalls the island and its Master Emerald, Knuckles takes it very personally and blames himself for not being able to prevent it. He will also not rest or take it easy until he is sure that his island and its treasure are safe once more. Despite his ties to his home however, Knuckles is very heroic and is willing to leave his duty whenever his help is needed. When not performing his duties, Knuckles prefers spending his time going treasure hunting.

Knuckles is somewhat gruff and has an equally short temper. Combined with his heroic morals, he is quick to anger when witnessing villains' despicable behavior. However, he is not the sharpest tool in the shed and will willingly jump into a fight without thinking once about the consequences. Regardless, he is very strong-willed and will not give up on his goals once he has set them.