Jeremy is allergic to cats, as he sneezes when Farmer Fitzgibbons' cat, Dragon arrives. He is voiced by the late Dom Deluise, one of only two voice actors from the original film to reprise the role in the sequel (The other being Arthur Malet as Mr. Ages).
Jeremy is a funny and clumsy black crow who is allergic to cats. He also appears to get scared rather easily as he seems to be faint-hearted of Dragon and the Great Owl. Despite this, however, he befriends the widow Mrs. Brisby and is shown to care for her slightly. Despite his clumsiness and incompetence he is the only character who directly attacks Dragon, successfully rescuing Mrs. Brisby from it. After she is left distraught at losing Timmy's medicine in the process, Jeremy seems to just lose track of conversation when suddenly he reveals he saved the medicine for her.
Jeremy first appears when Mrs. Brisby returns from Mr. Ages through a fallen tree. She encounters him trying to free himself from red string which he says is for a nest; Mrs. Brisby begins to remove the string but Jeremy claims he can see Dragon the cat approaching them but is mistaken for a rabbit. Afterwards, the real Dragon approaches from inside the log but is given away by Jeremy's cat allergy. Mrs. Brisby saves Jeremy who, in turn, saves Mrs. Brisby. He flies her to safety but she is devastated because she lost the medicine for Timothy (given to her by Mr. Ages). She is soon cheered up when Jeremy gives her back the medicine which he found. Afterwards, Mrs. Brisby continues her journey home with Jeremy in tow. He offers to fly her home but she declines saying that she is acrophobic (afraid of heights). He then flies away when Mrs. Brisby arrives at her house safe and sound.
In his next appearance, Jeremy flies Mrs. Brisby to see The Great Owl who tells her to go to the rats in the rosebush near the farmhouse who will move her house to the Lee of the Stone.
In his third appearance, Jeremy is apprehended (caught) by Auntie Shrew who ties him up in his own string. Auntie Shrew then leaves him but Jeremy is found by Mrs. Brisby's children who repeatedly asks where their mother is, (earlier he promised Mrs. Brisby to look after her children while she visits the Rats of NIMH and Nicodemus but also told him not to tell her children where she is).
Jeremy appears two more times before the movie ends, in his second to last appearance he is seen hiding in pond whilst Mrs. Brisby passes through to go home after hearing about the plan to move her house to the Lee of The Stone. He tells her that he was captured by Auntie Shrew but is distracted by Mrs. Brisby's amulet given to her by Nicodemus. She tells him to get all the string he can to form a lever and pulley system to make The Plan work. Although he does not appear in the house moving scene, he does appear afterwards where he arrived at the Brisby home with a bundle of string. There, he notices that the house has moved and ponders what he will do with all of his string until a female crow equally clumsy as him flies into him by accident. Jeremy then uses his string to make a love nest with 'Miss Right'. The film ends with Jeremy and Miss Right flying away into the sky together.