Draco Malfoy is a pureblood wizard who is taught to discriminate muggle-borns and blood-traitors by his parents, Lucius and Narcissa Malfoy. Although he grew up in a wello-ff family, his attitude was very poor. His family is deeply invloved in the Dark Arts. He became a Death Eater for his father (his father was sent to Azkaban) after the battle in the Department of Mysteries. He is constantly guarded throughout his time in Hogwarts by "friends" Gregory Goyle and Vincent Crabbe and former Head of Slytherin Severus Snape. Draco dated Pansy Parkinson in his time at Hogwarts. He also loathed Harry and the rest of the Gryffindors.
In the sixth book Draco had agreed to kill Albus Dumbledore, but failed. Then Snape killed Dumbledore because he had agreed to an Unbreakable Vow stating that he is to protect Draco and complete the task if Draco should fail, but also because he promised Dumbledore he would when the time came. It is revealed in the final book that as Draco disarmed Dumbledore, he became the master of the Elder Wand. In the chapter Malfoy Manor, Harry disarmed Draco in a battle after escaping the basement of the house. This meant Voldemort could not use the Elder Wand against Harry. Voldemort was then killed by his own killing curse.
In the epilogue he is married to Astoria Greengrass, the sister of Daphne Greengrass, a Slytherin in Draco's year, and fathers a child, his son Scorpius Hyperion Malfoy. Draco and Harry didn't become friends in the end of the story but are civil as they nod at each other at the train station at the end of the 7th book Harry Potter and The Deathly Hallows.