Alison Sedge regarded Jenkin as the most handsome mouse in Fennywolde. His looks, however, were often sadly marred by the bruises he received at the hands of his abusive father. Around his neck he wore his mousebrass, the Sign of Life. When Madame Akkikuyu saved Samuel Gorse and Young Whortle Nep from Mahooot, many of the owl's feathers fell out, and Jenkin took one and placed it in his hair. He called it his good luck charm, but he never revealed it as such to his pious father for fear of punishment.
Jenkin's father acted very cruel to him, giving the young mouse beatings if he did something Isaac found unacceptable. Often Jenkin would have bruises on his body, and initially it was thought that he was merely clumsy, but then the other Fennywolders began to realise the truth. Deep down, Isaac did love his son, but always blamed him for the death of his wife Meg who died giving birth to Jenkin.
Once, Jenkin had been in love with Alison Sedge, but after she received her Sign of Grace and Beauty his feelings for her diminished because she had become vain. However, Alison still cared for Jenkin even if it was hard for her to show it.
When Audrey Brown visited the field, Jenkin was immediately attracted to her. One night he got her out of bed and told her he was planning to build a nest around The Hall of Corn and he wanted to share it with her. He proposed to her but she turned him down, saying that she knew that he and Alison were meant to be together.
Soon after this, though, Jenkin and Audrey were chased out of the field by the now evil, animate corn dolly. However, when they reached the edge of the field, the corn dolly stopped chasing them. At first they thought they were out of danger, until Mahooot the owl picked Jenkin up in his talons, carrying him into the sky.
Sadly, Jenkin was killed and eaten by Mahooot, and Isaac discovered the owl pellet containing his son's mousebrass soon after.