While in 18th century Scotland, the newly regenerated Doctor, Ben and Polly meet a young Highlander named Jamie McCrimmon. At the end of the adventure, The Highlanders, it is Polly who convinces the Doctor to invite Jamie to travel with them. Be careful what you ask for, because Jamie becomes a fixture in the TARDIS for quite some.time.

After Ben and Polly decide to leave at the end of The Faceless Ones, Jamie continues on traveling with the Doctor. Jamie is eventually joined in these travels by Victoria Waterfield and finally by Zoe Herriotwhen Victoria leaves.

As one of the companions to travel the longest with the Doctor, Jamie develops a unique relationship with the Time Lord. The pair seem to fall easily into a lively, bantering friendship. Despite being confronted with many situations and creatures that might seem to be beyond his capability to understand, Jamie was able to quickly adapt and put things into a perspective that was accessible to his own mind.

Jamie was particularly fond of Victoria when she joined the TARDIS crew, and he felt it was his duty to protect her. Being a product of his time, Jamie is always solicitous and gentlemanly towards the women who travel with him. Because of her Victorian era upbringing, Jamie feels especially protective of VIctoria. He is quite upset when Victoria leaves the TARDIS, and almost decides to leave himself.

However, Jamie decides to stay on and they are soon joined by Zoe. Jamie initially finds Zoe's more modern attitudes and bossy nature irritating, but eventually adopts the same protective attitude disguised by the same bantering he engages in with the Doctor. Although Zoe is much more intelligent than Jamie, Jamie's common sense often trumps Zoe's intelligence in many of the situations the companions come across.

Jamie's travels with the Doctor come to an end on the battlefields of The War Games, when the Time Lords finally put the Doctor on trial for interfering with the universe. For his offenses the Doctor is forced to regenerate and exiled to Earth. Except for their first meeting with the Doctor, Jamie and Zoe's memories of their travels with the Doctor are erased, and they are returned to their own points in time. When last seen, Jamie is fighting an English redcoat back on the fields of Scotland.