James "Jimmy" Wilson is a childhood friend of Jennifer Lee. He is in love with her but she does not initially return the sentiment. He is portrayed by George Rainsford.
In Series Two, Jimmy gets a girl called Francine pregnant and they marry, although he does not love her - an unmarried woman with a child was a scandal in the 1950s. Their daughter's name is Caroline Francesca Wilson. Upon learning of Jimmy's new family, Jenny realizes she has to let him go, although she knows he was never hers to let go of in the first place. However, she lets go of whatever may have happened between them, and whatever happiness they could have found in each other.
This coincides with Jimmy becoming acutely and severely unwell with a bowel adhesion, which itself coincides with Jenny being seconded to the male surgical ward. Although the situation is uncomfortable, the pair are clearly glad to see each other. When Jimmy is rushed to theatre for an emergency bowel-resection, Jenny is there to ensure that mistakes are not made by a rude and incompetent surgeon.
When Jimmy and his collegue and friend Alec come to Nonnatus House for work, Jimmy and Jenny reconnect once again as friends, and Jimmy gushes over his new daughter, saying she's "the sweetest thing" he's ever seen. He expresses a wish for Jenny to be happy too, and, to that end, sets her up with Alec, who she eventually falls for. He is not seen again after this, even when Alec suffers a fatal accident.