Initially a reckless anarchist, Android 17 later reveals himself to be little more than a rebel without a cause. He finds joy in causing panic and acts on whims. Most of his choices during his initial appearance were motivated by what he simply called "The Game", referring to their quest to find and exterminate Goku.
While reveling in his enhanced might setting him apart from others, Android 17 hated his cybernetics that were forced on him, as Android 18 revealed when refusing Semi-Perfect Cell's attempts at convincing Android 18 into merging with him. This is likely because of the trauma he experienced due to being kidnapped by Gero. It may also be due to his love of nature, as he was no longer natural when Gero turned him into an Android.
When he is revived by Shenron because of a wish that restored both the lives of all of Cell's victims and all the damage caused during the Cell Games, Android 17 goes on to live a life of peace in obscurity. At the end of Dragon Ball Z, Android 17 provided energy for Goku's Super Spirit Bomb to destroy Kid Buu. He reappears in Dragon Ball GT when the scientists Dr. Gero and Dr. Myuu brainwash him telepathically, and he is eventually fused with Hell Fighter 17, a Machine Mutant version of himself created by the scientists in Hell, to form Super 17. Even without the ability to maintain his mind, however, 17 still exhibits sensitivity, mostly towards his sister. This is in stark contrast to Future Android 17, where he is a murderous sociopath who cares for no one but himself and his sibling. While under Dr. Myuu's control, he forces his transformed-self to reveal his own weak point, thus allowing Goku to kill him. On a related note, Android 17 also showcases some moral restraints, as when witnessing Cell brutally dispatch Piccolo, he, with clear horror and disgust, denounced Cell as a beast for what he did to the Namekian.
Android 17's strongest personal trait is his sense of self. He does his best to resist the will of Dr. Gero, and later, Dr. Myuu, and fights a futile battle against Cell to assert his identity and his pride. He is also overconfident in his power, believing that nobody was stronger than him and stalwartly denying it if someone said otherwise. This changed when he saw Cell and Android 16's strength in battle.
He is also somewhat sadistic, as he has a Colt M1911, using it against civilians in lieu of his own power. He seemingly finds amusement in the panic which he causes with it, in both Future Trunks' and the current timelines. This pistol can be seen holstered to his character model in Dragon Ball Z: Budokai 3.
As noted by his sister, Android 17 is somewhat similar to Goku, showing a childlike attitude at times. He often tries to find a fun means to accomplish his goals, as he made his attempt to locate Goku as nothing more than a game, even deliberately avoiding asking for directions in order to "play the game." Similarly, he has a tendency to go off the road during their travel to Goku's house simply because he thought it was "fun", much to 18's irritation. In the anime, when he holds up two hunters in order to trick them into donating their energy to Goku's Super Spirit Bomb needed to defeat Kid Buu, Android 17 says that they won the game before raising his own hand as well.
Android 17's rebellious personality has since been tempered by his occupation, as he channeled his somewhat anarchistic and childish tendencies into handling poachers and other persons of illegal intent or occupation within the Royal Nature Park with startling efficiency. His hyperactive nature merely lacked a proper focus before, and when given an ongoing objective, it can be seen that 17 is extremely focused and dedicated to achieving his goals. 17, however, did not lose his sense of humor in his work, as when he stopped the two hunters and tricked them into giving energy to the Super Spirit Bomb, he was clearly amused.
His slide into maturity is likely a contributing factor to his marriage. He also apparently has a soft-spot for children. Despite being relatively indifferent to reuniting with his brother-in-law Krillin, he was very warm to meeting his niece Marron. In addition, he had a child with his wife, plus adopted two more. It is possible that his decision to adopt two of his three children may have been influenced by his kidnapping at the hands of Dr. Gero.
By the time of the Universe Survival Saga, Android 17 has become much calmer than before, and is a gentleman, suggesting that he is more mature than he had been in the past. Whereas before he was random in his decisions, going purely on his emotional state, he now showed a more collected and pragmatic nature. He has also become very casual and humble, not showing much personal desire beyond providing for his family and protecting the wildlife. He also seems to take his opponents more seriously, a complete departure from his previous superiority-complex self and the murderously sadistic nature of his alternate timeline counterpart. 17 is shown to be very nonchalant and not swayed by any kind of news, even when learning of his potential death should Universe 7 lose in the Tournament of Power, initally refusing Goku's offer to participate despite the circumstances. He also apparently has a soft spot for children, while indifferent to meeting his sister. His child like attitude however is still very present as well as his desire to have a bit of fun while on his way to accomplish his goals, this was mostly shown in the Tournament of Power during his many fights with Universe 2 as he always played along with their over the top introductions and antics of love often playing the role of the "villain". However in times of crisis he is capable of being very serious, and even very heroic and this was mostly on display during his final living moments of the Tournament of Power with acts like throwing himself in front of the exhausted and injured Goku and Vegeta to take hits for them due to his infinite energy or even going as far as killing himself to save them from elimination at the hands of Jiren (although 17 is shown to have survived his own technique later on). Another newer personality trait is his tactical sense of fighting. While outclassed by the likes of Top and Jiren, 17 is able to still fight with them and hold them off for considerable lengths of time. This was mostly shown during his final stand against Jiren, where 17 was actually able to get inside of Jiren's head upon learning of his past and his wish for the Super Dragon Balls and was able to use this to give him a slight edge for a moment.
As shown from his choice of career, Android 17 is very outdoorsy, and finds it hard to sit still, seemingly stemming from his previously hyperactive nature. His love of the outdoors may have been influenced by the nature-loving Android 16, with whom 17 was close friends. 17's choice in a wife, a zoologist, may have been influenced by his occupation as a Park Ranger and enjoyment of the wild. 17 cares greatly for nature and was even willing to die to save it by taking on intergalactic space poachers and was willing to allow himself to suffocate in space to prevent them from blowing up. At the same time, not unlike his sister, Android 17 is not without a measure of materialist desire. His greatest dream is to own a large luxury boat, although it is for a simple goal of traveling the world with his wife and children. During the Tournament of Power, he showed much more concern for his sister's well being. When quickly realizing that she sprained her ankle, despite her denial of it, 17 quickly helped tend to it. Also, whereas before 17 would keep out of 18's battles or insist on fighting alone himself, he was shown in the tournament to work in great synergy with 18.
Android 17 appears to have a talent for behavior modifcation, as he managed to tame and reform the regenerated Cell Juniors to the point where he was able to work with and coexist with them despite their homicidal natures.
Android 17 (人造じんぞう人間にんげん１７号ごう, Jinzōningen Jū Nana-Gō), Lapis (ラピス, Rapisu) when he was an ordinary human, is the younger twin brother of Android 18 and Dr. Gero's seventeenth android creation, designed to serve Gero's vendetta against Goku. Despite his interests not initially deviating from this expectation, Android 17 takes it upon himself to kill Dr. Gero, who is uncooperative with Android 18's curiosity in activating Android 16 and deemed inferior by 17.
Android 17 makes a return a decade later in Dragon Ball Super, working as a national park ranger on a remote island, preserving wildlife from poachers. He is married and has a child, with two more children being adopted. He is asked by Goku to join Team Universe 7 in the Tournament of Power and due to Goku and Frieza's sacrifice to take out Jiren, he is left as the sole fighter remaining by the end of the tournament making him the winner, and thus the one who gets to make the wish on the Super Dragon Balls.