Because of the show's popularity and continuing positive ratings, season four was extended to twenty-three episodes, four more than any previous season. (Season one had just ten episodes, and seasons two and three had nineteen episodes each.) Besides, Creator James Duff revealed on an interview, that the extra episodes were given, because TNT didn't have much programming for mid-February, so they asked Duff to create a five-episode arc.

With an audience of nearly seven million viewers on average, its first-season ratings were the highest ever recorded for a new show on cable.

In an interview given the day after the show's cancellation, creator James Duff revealed that he and Kyra Sedgwick had a three-episode deal for her to act at some point on Major Crimes, but they could never worked out their schedules and a worthy storyline at the same time.

This spin-off was created, after Kyra Sedgwick decided she wanted to leave The Closer (2005), in order to spend more time with her family.

Once "The Closer" ended, and even though he appears in a lot of "Major Crimes" episodes portraying the same character he played in "The Closer", Jon Tenney is now listed as a "Guest Star".

The first episode of the show aired right after the series finale of The Closer.

Eric Garcetti, who plays Los Angeles Mayor Ramon Quintero on The Closer and Major Crimes, is the son of former LA DA Gil Garcetti, a consulting producer on both shows. In 2013, two years after his last appearance on The Closer as Mayor Quintero, Eric Garcetti was actually elected mayor of Los Angeles. After his election, he made another appearance as Quintero on Major Crimes, even filming a scene in his own office in LA's City Hall.

In major crime's Susan blommaert played the role of defence attorney Vivian green the same character she played in The Closer