Pete is one of only a handful of characters on Doctor Who that audiences meet in separate dimensions, including Companions Liz Shaw, the Brig, Mickey Smith, and ally Jackie Tyler (though we only meet her doppelganger very briefly). First introduced as Rose’s father who’d died when she was a baby, a bit of a dreamer and get-rich-quick schemer who, though his heart was in the right place, wasn’t the best husband, the Pete we spend more time with is an incarnation from an Alternate Dimension, affectionately called “Pete’s World” by the Doctor. This version found success with one of his early schemes and is a well-respected, incredibly wealthy executive and inventor. In this timeline, though he and Jackie married, they never had any children, leading to somewhat strained interactions with Rose when he realizes their connection. It turns out that Pete is working under deep cover within the company manufacturing Cybermen in an attempt to bring them down. He teams up with the Doctor, Mickey, and Rose, eventually forming close ties with Rose and marrying Jackie.
Read More about Doctor Who Ally Profile: Pete Tyler