Jenkins was Haley Dunphy's driving teacher who appeared in "Fears".
Jenkins gave Haley two driving lessons off-screen before the episode he appeared in. Those two times, Haley failed, one time driving into the bushes as Alex mentioned, and he yelled at her, causing Haley to think of him as so mean.
In "Fears", Haley was constantly thinking that Jenkins hated her only for Claire to contradict her. Jenkins first appeared when coming out of the drivers building with a driving test clipboard and when Haley noticed him, she got upset and hoped that she would not be with him again and passed her. When she thought he was not with her again, Haley said "Oh, thank God", only to then hear him say "Well, come on. I don't have all day." meaning she was with him again (Oh no!)! Haley said that she was going to throw up, but Claire told her to get in the car, put on her seatbelt, take three deep breaths and relax and Jenkins then said "Yo. Let's move it, Two Strikes." and Haley set off with him, scared.
During the test, he told her to turn left at an intersection, but instead went right. Jenkins got furious and shouted a little bit and Haley said that she was trying. Jenkins told her to pull over, but Haley refused saying that she could do this, but Jenkins shouted "Pull over now!" and when she did, the camera cut to Haley crying. Jenkins asked why she was crying and Haley asked him why he hated her to which Jenkins replied that he didn't hate her, that she seemed like a nice girl and that she reminded Jenkins of his daughter... which is why he wanted Haley to live a long and happy life and be safe, and not hurt his daughter.
Haley said that she really wanted her license and she swore she had been practicing a lot. Jenkins asked her if she would drink and drive or text and drive (separately) and Haley's answer to Jenkins's two questions were "No, sir.". Jenkins decided that they should start from the beginning, although Haley asked him if he could smile first because if he smiled, she would be less nervous. And so, he gave Haley a smile, only for Haley to reply "Okay, that didn't help." and Jenkins replies "Just go."
Jenkins's final appearance was when he and Haley returned to the drivers building where Claire and Alex still were and Haley had managed to earn her driver's license and ran out happily, but nearly lost it when she forgot to put the brake on with Jenkins still inside the car and the car was not in park, and so Jenkins put the brake on instead. Claire then told Haley to run fast to the counter which she did as Jenkins stared after her, but was then staring at Claire and Alex.