Dick is the son of John and Mary Grayson, who were trapeze artists in Hayley's Flying Circus. Dick's family is killed by mob member Tony Zucco, and is taken in by billionaire Bruce Wayne. Bruce reveals himself to be Batman, and Dick decides he wants to join Bruce in hunting down his families killer by taking on the mantle of Robin. Dick fought by Bruce's side, eventually forming the Teen Titans with other teen superheroes; Kid Flash, Wonder Girl, Speedy and Aqualad. When he was 18, he and Bruce got into a huge fight and he quit being Robin. He then took on the mantle of Nightwing, and while having reconciled with Bruce, he still operates mostly in Bludhaven rather than Gotham.
Dick is the older adoptive brother of Jason Todd, the second Robin who died after being Robin for two years. He later becomes the older brother of Cassandra Cain, the fourth Batgirl. He then becomes the adoptive brother of the third Robin, Tim Drake, who he already had a very close brother like bond with before his official adoption. When Damian Wayne, the fifth Robin, enters the picture, he becomes his older brother as well. When Bruce is believed to be dead, Dick takes up the mantle of Batman and takes on Damian as his Robin.
Dick has had many romantic relationships throughout the years. Most notably his engagement to Koriand'r aka Starfire. As well as his relationship with Barbara Gordon aka Batgirl and Oracle. He's also been romantically involved with Helena Bertinelli.