Observers have noted strong similarities between Brenda Leigh Johnson and Jane Tennison, Helen Mirren's lead character in the British crime drama Prime Suspect, with USA Today calling The Closer 'an unofficial Americanization' of the British drama.

Kyra Sedgwick has acknowledged that the show owes 'a debt' to Prime Suspect, and her admiration for that show and for Helen Mirren was one of the factors that first interested her in the role.

Gina Ravera was the only regular cast member to leave the series before its end, departing after season four; her character, Detective Irene Daniels, was written as having transferred to another division.

Mary McDonnell joined as a recurring character (Captain Sharon Raydor) in seasons five and six before becoming a full-time cast member in season seven, and she went on to star in the spin-off series Major Crimes.

TNT announced on December 10, 2010 that the show's seventh season, which began production in spring 2011, would be its last, stating the decision to end the series was made by star Kyra Sedgwick.

The final season was extended to add six extra episodes to the usual 15-episode order, building toward the spin-off series Major Crimes, which premiered right after the finale.

The Closer's debut episode was watched by more than 7 million viewers, making it the top-rated premiere episode ever of an original scripted series on basic cable at the time, a record then broken by the show's own second- and third-season premieres.

At the end of season three, The Closer became ad-supported cable's most-viewed scripted series of all time, and its season-three finale still holds the record for the largest live + 7-day audience for a single episode of an ad-supported cable series, with 9.55 million viewers.

Until the 2011 Primetime Emmy Awards, Kyra Sedgwick had made television history as the only actress ever nominated for an Emmy, Golden Globe, and Screen Actors Guild award every single year the show aired within the eligibility period.