Dan Sullivan made his first appearance 7 June 1999. He was the hunky ex lover of Bianca Jackson. Dan had another fling with her and eventually bought the Vic for a fiver off Phil Mitchell. Dan betrayed Phil and was forced out of the area. Dan was played by Craig Fairbrass.
Dan was born on the 28 November 1966, he had a sister. He gained a reputation as a petty crook. One time he had a brief affair with Bianca Jackson.
Dan arrives in Albert Square as Carol Jackson's latest boyfriend in 1999 and they plan to marry on discovering she is expecting his child. Carol's daughter Bianca is stunned to see him, as they had had a fling when she was a teenager on holiday, many years before. Dan and Bianca begin an affair, which is discovered, leading Carol to have an abortion and leave Walford. Bianca also leaves Walford. Dan stays in the Square and buys Grant Mitchell's share of The Queen Victoria public house from his brother Phil Mitchell for only £5, as Phil wanted to sell it for that measly price to spite his estranged mother Peggy Mitchell. Dan and Phil become good friends but Phil and his mother call a truce. Phil then feels Dan took advantage of him when he was not thinking straight, and demands the pub back, but Dan knows about Phil's dodgy deals so Phil backs off. Dan then discovers that Phil, Roy Evans and Frank Butcher are running a dodgy scam involving the car lot, so he informs the police. He later tells Melanie Healy about this and she tells Lisa Shaw, leading to Phil finding out. Phil feels betrayed by his friend and is angry. Phil plots to win back his share of the pub and arranges a card game. When Phil wins the share back and smugly refunds Dan's £5, Dan vows revenge. He threatens Mel with phone calls and begins stalking her because she had told Phil about him informing the police and she was in on Phil's plan to throw him out of the pub. Mel is saved when her fiance Steve Owen rescues her, threatening to kill him by holding a gun to his head, unless he leaves the Square and Dan leaves Walford in July 2000.
Six months after he is last seen, he returns, wanting revenge against Phil. When Phil is shot on Steve and Mel's wedding day, Dan is a suspect, but Phil's ex-girlfriend, Lisa Shaw is responsible. Phil forgives her and decides to frame Dan instead. Dan is arrested and in court, the jury rightly find him not guilty, and he gets revenge by kidnapping Mel - thinking Steve had shot Phil. Dan gets £200,000 ransom, and leaves Walford in August 2001, considerably richer than when he first arrived and has not been seen since - although he leaves flowers on Steve Owen's grave, bearing the message "Gotcha!".
In 2003, Phil's cousin Billy hears news that Dan is back in town to settle a few scores, although this is off-screen. This is later revealed to be a hoax by the police to connect Phil to the alleged murder of Lisa. Dan is last heard to be living in Spain, but having many brushes with the law, just like he did in the square.