Debbie Gallagher (born 27 January 1993) is the fifth Gallagher sibling. The daughter of Frank and Monica, her brothers are Phillip, Carl and Liam; her sisters are Fiona and Stella; her half-brothers are Ian and Nigel; and her half-sister is Delia. Although Debbie is only 16, she is old beyond her years and since Fiona went to Amsterdam with Steve McBride, Debbie is often tasked with saving the family from ruin. Originally Debbie was a slightly unusual and awkward child, albeit highly intelligent and resourceful, but since Fiona's departure, Debbie quickly became head of the household and took care of duties such as cooking and taking Liam to school. As a consequence, Debbie missed out on socialising and has become mature beyond her years.
In series one, Debbie had once abducted a three year old boy, because she "wanted a sister. But none of the girls on the estate would take the chocolate". So she dressed him up in girls' clothes. The child's disappearance compelled the majority of the estate to go up in arms in search for young "Jody". When Debbie finally admitted what she did to her family, a furious and bewildered Fiona, Steve, Lip, and Ian, formulated a plan to return the youngster back to his family without incriminating Debbie. After circulating false rumours of sightings around the Chatsworth Estate for much of the day, Debbie emerged as the hero of the hour when she returned the boy to his distressed family.
Debbie's closest familial relationship is with her father, Frank. Unlike Fiona, Lip, Ian and Carl, Debbie admires him and often shows her love for him, often seen to be the most affected when he is in danger or trouble. This often leaves her the most vulnerable to being let down by him, but Debbie's loyalty to her father is occasionally rewarded, and it is strongly suggested that Frank appreciates 'Little Debbie' more than anyone else in the world. Debbie also detests her mother more than the rest of the family, refusing to forgive her for abandoning them years ago or for her continued laziness and self-absorption. She did respond sympathetically when more details became clear regarding Monica's abusive childhood at her mother's hands. In contrast, Debbie was close to Frank's ex-wife Sheila.
Debbie's relationship with the rest of her family is generally good: she sees her siblings as her dependence and generally supports them through their various misadventures; and they generally recognise all she does for them. She's particularly protective of, and very close to, her younger brother Liam, and has enlisted his help on some of her schemes. She can also be seen to forge strong relationships with other characters, notably Marty and Mandy Maguire.
It is revealed in Series 5 that Debbie has been in a secret relationship with police officer Tom O'Leary, despite the fact that she is only 15 years old. Debbie and Tom break up at the beginning of series 6 during her 16th birthday party when she realises that Tom is too old for her and that he wants much more from the relationship. Tom begins to stalk her, although he tells workmate Carrie that Debbie has been stalking him.