Jem is Scout's older, brother, nearly 10 years old at the start of the novel and nearly 13 at the end, just entering puberty.
He is close to Scout: he is her constant companion at home. Although as he gets older he becomes positively allergic to Scout in public and spends more time with a football team than Scout, he always looks out for her and protects her.”Jem had his little sister to think of”. pg 20.
He loves and admires his father, which is one of the reasons why he was so furious with Mrs Dubose and beheaded all her camellias.”Jem was scarlet…he did not begin to calm down until he had cut tops off every camellia bush Mrs. Dubose owned”.
He sees himself as brave and casts himself in the hero role in their games.”Jem had never declined