Chloe's father married Trish Webber and they had Chloe together. He was a criminal who regularly abused Trish and Chloe.
When times were rough, Trish would sing "Kookaburra" and, for Chloe, everything bad seemed to disappear, even her father's violence. He died in 2011 when he crashed his car.
In 2012, Chloe became mentally linked to a young Isolus which enabled Chloe to turn people into living drawings and to make drawings come to life. Chloe drew her father, who became an increasing threat to the Tenth Doctor and Rose Tyler, who were trying to free Chloe.
When Rose helped the Isolus escape from Earth, the drawing of her father came to life, intent on hurting Trish and Chloe. Trish sang "Kookaburra", and when Chloe stopped being scared, her father vanished. The drawing never fully manifested into a monster that could attack them, remaining suppressed by the efforts to dampen Chloe's fears of him until the Isolus broke its connection with Chloe once it had been given the means to leave Earth and reunite with its family, through the recovery and reactivation of the pod it used to travel through space. (TV: Fear Her)