Keiko was introduced as a romantic interest for the recurring Next Generation character of Chief O'Brien, and stories involving her and the couple's children allowed Star Trek to expand its narrative beyond weekly space missions.

[6] The character appeared prominently the following season in the episode "Disaster", in which she gives birth to Keiko and Miles' first child Molly in the crew lounge Ten-Forward during a shipwide crisis.

[6] Keiko is a central character in the sixth season episode "Rascals", in which she is temporarily transformed into a child and played by Caroline Junko King.

In the fourth season episode "Body Parts", Keiko and her unborn child are injured, and to save the fetus it is placed into Major Kira's uterus to carry to term, as an in-story explanation for actress Nana Visitor's pregnancy.

The couple and Kira form an awkward ad hoc family for the duration of the pregnancy, until their son Kirayoshi is born, in the fifth season episode "The Begotten".

Some criticized her as unlikable and "shrewish", based on her abrupt (and short-lived) cancellation of her wedding to Miles, and her domestic expectations of him in Deep Space Nine episodes.

[1] A Screen Rant article argued, "It's a struggle to come up with any compelling reasons why Keiko needed to exist", and that the character overall "hurt" The Next Generation.