Ron Stoppable (full name: Ronald Stoppable) is the best friend, sidekick, and later, boyfriend of teen hero Kim Possible. He was born to Mr. and Mrs. Stoppable (first names unknown), a Jewish couple living in Middleton (a city somewhere in the mid-United States, state unknown).
Ron's friendship with Kim began when they were in pre-kindergarten. (In a time-loop story, "A Sitch In Time", Ron tried to come to Kim's rescue when the "juvenated" Dr. Drakken, Duff Killigan, and Monkey Fist were teasing Kim on the pre-K playground. But those events were erased when the time-loop was closed.) They've gone trick-or-treating every year since then (the first time, Kim went as a cowboy, and Ron as a ballerina), until their first year of high school. Ron wanted to go with Kim as a horse (in a two-person horse costume), but Kim wanted to attend her friend Monique's Halloween party. Ron ended up going with Josh Mankey, Kim's crush at the time.
Ron was on the cheer squad with Kim their first 3 years of high school, playing the part of the Middleton Mad-Dog. (His costume came complete with mouth foam [a sign of rabies].) When he first proposed the Mad-Dog character, the other cheerleaders didn't think much of it, and Kim - the squad captain - was herself reluctant to allow him onto the squad. But after an incident with Dr. Drakken (a former classmate of her father who turned evil after Dr. Possible and his friends laughed at Drakken [then Drew Lipsky]), Kim let him show off his Mad-Dog character at a basketball halftime. The crowds loved him, and he continued being the Mad-Dog until his senior year.
Ron's pet is a naked mole-rat named Rufus, named after Ron's invisible friend he had when he was four years old. He had to narrow his choice of pets to hairless pets, as his father is allergic to all types of fur. Rufus was purchased at the Middleton Smarty Mart, and goes almost everywhere with Ron, nesting in a pocket of Ron's cargo pants.
Ron and his family are somewhat observant in their practice of Judaism. Ron has passed his bar mitzvah, and used the certificate his rabbi presented to him as part of a collage about his life. However, Rabbi Katz forgot to sign it, which Mr. Barkin (subbing for the normal teacher) said invalidated Ron's passage to manhood. Ron later coincidentally met up with Katz in Las Vegas during a mission. Katz discounted Barkin's assessment of the unsigned certificate, assuring Ron that he was indeed a man. Other aspects of Judaism, such as following the laws of kashrut (keeping kosher), are not observed. For example, Ron eats quite often at Bueno Nacho, whose menu items clearly violate the prohibition of eating meat and dairy products together. He also once joked to the lunchroom lady about "calling ahead for the kosher meal", but then accepting the standard mystery meat meal.
Kim started up a web site - kimpossible.com - to advertise her services, mainly baby-sitting. But through a mis-typing, a security specialist and his millionaire customer called on her for help when they were trapped by a laser security grid. Ron went along, and with Rufus's help, unlocked the millionaire's gate, allowing Kim to perform her first non-babysitting job. After that, Kim and Ron went on many missions, helping a vast variety of people: national park rangers, corporate CEOs, little old ladies, etc. Ron's role is usually secondary, since he initially was more scared than brave. (But that changes in time.) Ron's mis-steps often foiled Kim's attempts to capture criminals, but they also inadvertantly aided her in the end. (This "Ron-factor" was investigated by the covert organization Global Justice, but they decided it was a non-factor.)
Ron has several phobias, mainly to monkeys and spiders. (The former came about when he was assigned a cabin at summer camp that also housed the camp's wild mascot, a monkey.) This was a source of conflict on one of their early missions. Kim aided an anthropologist, Sir Montgomery "Monty" Fisk, in collecting a monkey idol from a Cambodian cave. Ron was convinced he was "500 miles of bad road", but Kim dismissed it as Ron's aversion to monkeys. The idol ended up being stolen from their camp, by a disguised Fisk, masquerading as a ninja. When Kim couldn't go back to Fisk to ask him questions (she had to visit her nerdy cousin Larry), her web-site tech Wade generated a holographic-Kim (unknown to her and Ron) and sent it and Ron to Fisk's castle. While there, Fisk thought they had uncovered his ruse, and admitted to stealing the idol to complete a set of them which gave him mystical monkey powers. He renames himself Monkey Fist, and attacks the holo-Kim. It's then revealed that Kim wasn't really there, leaving Ron alone for the first time on a mission. As Ron is being chased about the castle, Kim's cousin Larry is replaced as Wade's hologram, and suggests to Ron that he also use the idols. He bathed himself in their energies, and obtained the same mystical monkey powers, including monkey kung-fu. He used them to defeat Monkey Fist and to destroy the idols.
Kim's nemeses often overlook Ron's presence, dismissing him as a buffoon, and almost always forgetting his name. (The one exception is Monkey Fist, who Ron considers his own arch-nemesis.) This is often is their demise, as Ron's efforts often disable the mechanizations of whatever foe that he and Kim are facing.
Ron has also had his share of solo adventures. Because of his exposure to the monkey idols, the Sensei of the Yamanachi School (a secret ninja high school in Japan) arranged to have Ron as an exchange student. He did this so that Ron can help fight Monkey Fist, who has stolen the Lotus Blade, a mystical weapon that is only controllable by those exposed to the mystical monkey idols. Just as Ron is overlooked by Kim's nemeses, so too Monkey Fist overlooked Rufus. Rufus, being in Ron's pocket at the time, was also exposed to the mystical monkey powers. He is also able to control the Lotus Blade, and helps to defeat Monkey Fist.
Ron is usually unsuccessful with girls, but not for lack of trying. He eventually has a brief relationship with Zita Flores, a ticket girl at the movie theatre. He is also oblivious to whether girls like him. In their junior year, Kim revealed to Ron that another cheerleader, Kara, had liked him. Also, a girl at The Yamanachi School, Yori, likes Ron, which Kim also pointed out to him when he encounters her again.
At the end of their junior year, Kim and Ron realize their attraction to each other, and began dating. As the senior year begans, Ron was afraid of losing Kim, and "secretly borrowed" her super suit (an invention of Wade's that eventually proves to be unreliable) to win the quarterback position. After his deceit is revealed, he admits this to the coach, Mr. Barkin, who "punishes" him by making him the running back.
During their senior year, Ron's parents adopted a baby which they named Hannah. She was actually the incarnation of an ancient weapon, the Han, and was secretly presented for adoption by Sensei. Ron initially feels threatened by her, being used to being an only child, but quickly comes to love Hannah. While baby-sitting her, Ron believed he was just playing games with her. But he was unknowingly training her to defend herself, when the opposite weapon, the Yono, appeared. She defeated Yono and Monkey Fist, and returned to life as the youngest Stoppable.
When the last week of senior year arrived, Ron began having anxiety about striking out into the real world. These fears came to a head when Warmonga and her fellow Lowardian warrior Warhawk come to seek revenge against Kim over a prior defeat at her hands. They kidnap her during their graduation, as well as Drakken, another player in the previous encounter. It is then that Sensei appeared again to Ron, telling him that his destiny as the ultimate monkey master was coming to fruition. Ron and Shego, Drakken's hired hand, used one of Dr. Possible's space shuttles to go rescue Kim and Drakken. After the rescue and return to Earth, the Lowardians follow. During the final battle with them, Kim is knocked out. Ron's monkey powers arise, and he defeats the Lowardians and frees the Earth. The graduation continues, with Ron adding his own style to the ceremony by flying by rocket-pack to accept his diploma from Mr. Barkin. He and Kim attend the graduation party, departing in Kim's flying car, and kissing under the moonrise.