In spite of the many Klingon-oriented episodes of Star Trek: Deep Space Nine (1993), this marks the only appearance of the Klingon homeworld Qo'noS on the series.
One of the reasons the writers wrote Keiko out of the show for 6 months was to give them room to explore the O'Brien/Bashir friendship.
Stephen Hawking visited the set during the filming of this episode. Armin Shimerman recalled: "I remember I turned, and the smoke seemed to part, and there was Dr. Stephen Hawking, visiting the set with Rick Berman". Shimerman considers meeting Dr. Hawking as a high point of his life and has a photo of himself with Hawking.
Grilka's beaming command while holding the unconscious Quark is the same as the one Kirk gives to Maltz while holding Spock in Star Trek III: The Search for Spock (1984).
When Quark introduces himself to the High Council, he states his father's name as Keldar.