Frankie was officially introduced in the movie while singing in his jazz ensemble conducted by Franny Robinson. After landing on Lewis' hat, Lewis saw that he had Bud's denture. At the end of the number, Bud squeezed Frankie to propel the teeth from the frog's mouth to his own.
At dinner, Frankie is seen singing with the other musical frogs on the chandelier above the dinner table. During the meatball fight between Franny and her brother Gaston, Frankie calmly moves his microphone to dodge one of the flying meatballs.
Frankie is next seen arriving at the frog's personal outdoor bar, where he tells a joke about a bullfrog at his friends' insistence. Bowler-Hat Guy then discovers them, and comes up with the plan to take over one of the frog's minds in order to kidnap Lewis. After the bullfrog joke, Frankie goes to buy a fly from a vending machine, eats it and subsequently is taken over by Bowler Hat Guy and Little Doris, agreeing to be his minion. Frankie goes to the dining room to make his attempt, but says that because there were a lot of people and that he has little arms, he couldn't do it, and says that the plan might not have been well thought-out. At the time machine, Frankie is then released and Little Doris drops the frog to some unknown location on the ground.
After the T-Rex who attacked the Robinsons was released from the control of Little Doris by the little hat being knocked off their head, two of Frankie's friends took Little Doris to the trunk of their car and threw it in. Frankie strode to the car, then snapped his fingers and the two of his friends closed the trunk.
At the end of the movie, during the science fair, a frog named "Frankie" by the child Franny jumps on Bud, then is retrieved by Franny, reprimanded for running away and unceremoniously thrown in her frog box.