While out at the beach, Sora accidentally trips over Jonathan as he lays on the sands. Sora brings Jonathan back to her dorm room and asks Fool to watch him. When he does, he tries to predict the seal's future only to Jonathan believing he's a fish and tries to eat him. He sneaks out of Sora's room and meets Layla, who is spooked by the baby seal. Sora and Ken are out getting him fish when they hear Layla's scream and Layla demands Jonathan is removed from the stage. Sora continues to support Jonathan in her room to the point of collapsing (she takes a part time job to pay for Jonathan's food). With Anna and Mia, she competes in a juggling contest to win the money for Jonathan's food. Jonathan ends up showing off his juggling skill to a clumsy Sora during the show (Fool's second telling of Jonathan's future comes up as the Wheel of Fortune showing a lucky future for the seal). Eventually, Sora tells Kalos what is going on and after some convincing, Kalos lets Jonathan live at Kaleido Stage. For most of the series, he is seen riding atop Marion's head. He is a funny and intelligent creature.
Nothing changes much with Jonathan except he only performs with Marion on the Kids Stage and he seems to be developing his own personality.
Jonathan appears in the following Kaleido Star OVA's and sings a song along with Marion called "M&J" on the Kaleido Star Character Song CD. In the third OVA, Marion and Jonathan talk about some seal facts while also teaching Sora to speak seal (which Sora fails at first).
- He is one of the few characters to be able to see Fool - albeit in very comic circumstances.