Peter Alan Tyler or Pete, was the deceased father of the Ninth Doctor's companion Rose Tyler and the husband of Jackie Tyler.
Pete was a jack-of-all-trades and a budding entrepreneur who was constantly involved in various money-making schemes, from selling flavoured health drinks (named "Vitex") to trying to market solar power panels. Most of these schemes were unsuccessful, however, leading to tension in his marriage to Jackie, Rose's mother. Jackie also accused Pete of cheating on her on a few occasions. Pete was born on 15 September, 1954 and died on 7 November, 1987 in a hit-and-run accident when Rose was about a year old.
Rose asked the Doctor to take her back to 1987 so she could witness her father's death. Jackie had told Rose as a child that her father had died alone, and Rose wanted to be there for him. When she was faced with the reality of what she was seeing, however, Rose impulsively rushed forward and saved Pete from being run down, changing history and causing a temporal paradox that damaged time. This attracted the destructive Reapers, who began to "sterilise" the wound in time by devouring everything in sight.
Pete eventually figured out that Rose was his daughter and on listening to her describe what an ideal father he had been, also realised that Rose was lying to cover up the fact that he was supposed to be dead. The presence of Rose awakened Pete's paternal instincts, and to save everyone and restore history, he deliberately stepped in front of the car that should have killed him, dismissing the Reapers and putting time back on track. History did change to a small extent, however — this time the driver did not flee the scene and Rose was there to hold his hand while he was dying. Pete died with a smile, while looking on his daughter's face ("Father's Day").
Although Pete was gone, it was his persistent spirit that Rose inherited, and a penchant for (as Jackie put it) "mad ideas" that pushed Rose to keep trying even when all hope seemed lost and save the world again.
Rose met Pete again, this time on an alternate Earth where he did not die ("Rise of the Cybermen").