He is also somewhat careless as he accidentally destroyed a Galactic Monument with his ship's weapons and is noted to be a bumbler by his superiors. He also seems to be somewhat incompetent as he was supposed to kill the young Goku to prevent him from destroying the Earth and he failed in that casting doubt on his status as an elite patrolman. While known for his sarcasm and snide remarks, Jaco also possesses a perverted side, such as commenting how low Bulma's breasts have fallen since becoming a mother and making a comment on her and Vegeta's 'pillow talk' (marital intimacy) when he learned she was married to the Saiyan Prince. He also hates to be called short, as he nearly killed a civilian for it.

He is known to be afraid of Bulma for her flaring temper, although he often offends her by commenting her appearance, showing he can be quite obtuse and he has shown to fear Vegeta for his notorious reputation as the Saiyan prince. He also tends to get panicked quite easily if it involves his own well-being. He also chose not to arrest Beerus or Whis for manipulating time out of fear. When he saw Beerus personally, he was shocked that he really existed and tried to get a picture but stopped after Bulma stated he might get destroyed. He disregards myths, which was shown when he did not believe Bulma when she said her husband was training with Beerus, the God of Destruction. He usually reacts this way when faced up against some of the most powerful warriors in the universe. He can also be cowardly, as he attempted to flee when Golden Frieza arrived, despite his duty to protect the Earth, and chose not to arrest Beerus or Whis for manipulating time out of fear (even though he criticized Bulma for bringing this up). However, this idea may be due to his extreme loyalty to his planet, so he will agree with their views on humanity. He also views anyone who cannot live up to his expectations as inferior.

He is also somewhat blank, as he was willing to use an Extinction Bomb to wipe out humanity just because Omori criticized them. Jaco is an alien who has a large amount of pride in his duties.

Jaco plans pistol