Much like the wind, Sonic is free-spirited and always on the move. He has a passion for adventure and is very much a thrill-seeker, always looking for the next thrill, challenge, and triumph. For Sonic, speed is a way of life; he runs fast, thinks fast, and even eats fast. Being addicted to speed and action, Sonic gets bored and restless during extended times of peace. In fact, Sonic cannot process the aspect of being restricted and being unable to move around very much makes him extremely stir crazy. He acts on instinct and lives in the moment, though he is very impatient, impulsive and tends to run headlong into trouble without a plan. While he can be shortsighted of others' feelings (making him blunt, honest, and rude to a fault), his heart is nevertheless always in the right place.

Sonic's typical driving force is his immensely large, self-obsessed ego, yet his demeanor is normally laid-back, cool and carefree. Possessing a snarky tongue and sassy attitude, he is cocky, brash, quick-witted and often jokes around even in dire situations. He likewise has a playful, albeit never mean-spirited, arrogance about him and likes to play small pranks.  When the situation calls for it though, Sonic can be serious and will immediately rush to aid those in dire need. Always on the heroic side of things, Sonic is very benevolent with a strong sense of honor, justice and fair play, being fully committed to helping out those in need at all times. Sonic also does not back down or give up, because he has an unwavering belief and faith in himself and his abilities. Sonic is also noted to be very courageous. However, he suffers from a severe case of aquaphobia which has only worsened with time. He is also a bit of a slop at times, and chores do not sit well with him.

While he often acts like he does not care, Sonic is rather protective of his image. To this end, he will get rid of any documentation and preferably dodge any performance that does not show him looking cool, even if it means his friends will look bad. He is likewise uncomfortable about being open about his feelings and actively tries to dodge such conversations, presumably because he considers them uncool. However, he is willing to lower his guard for the sake of his friends. Sonic can also get rather over-competitive when contending with another, prompting him to let things get way out of hand out of overconfidence. In case he loses a competition, Sonic becomes obsessed and borderline crazy about settling the score with his opponent, as he cannot accept the fact that he can actually lose. Despite having his own fair share of quirks and willing to fool around just for the sake of it though, Sonic is very grounded and has a profound common sense that often makes him the "straight man" amongst his friends.

Though rather selfless when saving the Village, Sonic does come off as somewhat sensitive about his hero-status, becoming extremely jealous, defensive, and frustrated whenever someone else rivals his fame, steals the spotlight or when the civilians turn against him. As such, when deprived of the chance to be the hero, Sonic gladly springs into action when he gets the opportunity to save the day in the end. This mindset even led to him temporarily retiring due to how ungrateful the citizens were for his efforts. Even so, when the times really call for it, Sonic will forgo his opinions to help those in need. Sonic is also a true chili dog enthusiast who can identify the ingredients of a chili dog with one bite.

Sonic is noted to be strongly loyal towards his friends. Though he does not always show that he enjoys others' company (mainly because he finds himself too cool for that), he nonetheless cares deeply for his friends and will do anything for them. Early on though, Sonic was somewhat of a loner and cynical. While he was willing to work with his friends in times of need, he would show more interest in going out alone and would even take credit for what the team did collectively. In time though, Sonic grew to see how his team made him stronger and realized that his friends were his strength. Since then, Sonic has become a much more admirable team leader, being quick to ask for help and acknowledge their collective contributions. Regardless, Sonic's confidence and impatience tends to get in the way of his team spirit, as he sometimes feels that things will get done more quickly if he handles them alone. This attitude also makes him kind of snarky and boastful in the faces of his friends at times. Although Sonic usually defends his actions in such cases, he is nonetheless capable of admitting he was wrong in such situations. He also strongly believes in the friendship his team shares and will never do anything to compromise it; Tails in particular has noted that Sonic will never give up on his friends, "no matter how bad things get.”

He is voiced by Roger Craig Smith, here is an example of his voice work: https://youtu.be/c_qp2mg94EY?t=26