Slinky Dog, also known as Slinky or Slink, is a toy dachshund with a metal slinky for a mid-section, who speaks with a southern accent

In Toy Story, he likes playing checkers with Woody. He is also one of the toys who believes it was an accident when Woody knocks Buzz. He is not happy about Woody's disappearance. He catches the lights when Woody calls them in the window until a grumpy Potato Head snatches it. He then goes away when seeing Buzz's arm by closing the curtains of Andy's window. He is also guilty when he see Woody telling the truth and holds Woody in order to help them, but when RC is tired, he loses his grip on Woody and gets stretched out and his slink is broken when they dodge as RC is tossed because his head and hind are in both sides as they pull it backwards, his slink is destroyed, until it is fixed at the end of the film.

In the beginning of Toy Story 2, Slinky is the one who finds Woody's hat, which he describes as the "good news," but describes the "bad news" as where he has found the hat. After Woody is stolen by Al McWhiggin of Al's Toy Barn, Slinky joins Buzz, Hamm, Mr. Potato Head and Rex on a mission to rescue Woody. His springy coil is used as a bun-gee cord when the toys jump from the roof of Andy's house. When the toys break into Al's apartment, Slinky uses his string to hold Jessie and Bullseye back by coiling them up so the toys can safely rescue Woody. After Al packs Woody and his Roundup gang and heads for the airport, Slinky, suspended from the elevator ceiling by Buzz, Hamm and Potato Head (while Rex watches the duel between Buzz #2 and Zurg), reaches for the case that contains Woody. Just as he opens the case and grabs Woody's hand, the elevator reaches the lobby and Al walks out, causing Slinky to stretch out until the Prospector pulls Woody back into the case, causing Slinky to lose his grip on Woody and rebound. When the toys carjack a Pizza Planet delivery truck, Slinky controls the pedals of the vehicle. At the airport, Slinky assists Buzz when the toys split into groups, but his hind-body gets hooked onto a luggage handle behind him and is unable to follow Buzz as he once again gets stretched out; nevertheless, he manages to catch up with Buzz and the other toys as they capture the vile Prospector. After the toys return home, he is seen alongside Buster barking at the door and calls to the toys to help the dog exit the room (done by Jessie). In an outtake, Slinky is seen caressing his hind-body after catching up with the group.

In Toy Story 3, Slinky is still very loyal to his friends, but is heartbroken when he believes he and the other toys are thrown out by Andy. At Sunnyside daycare, he is seen being tangled up constantly by the young children, and is easily dispatched by Lotso's gang and imprisoned. He is seen the be the happiest toy to see Woody return, and helps his best friend subdue the Monkey toy who monitors the security cameras. When the toys end up in the junkyard, Slinky is the first to be sucked up by a magnetic ceiling due to his metallic rings in his body. When the toys are rescued from death by an incinerator, he is the most vocal about wanting to get revenge on Lotso for leaving them to die. He and the other toys are eventually donated to Bonnie, a little girl who took Woody home earlier in the film.