The series originally focused on Teresa Giudice, Jacqueline Laurita, Caroline Manzo, Dina Manzo, and Danielle Staub. Dina Manzo and Staub left the program during the second season, and were replaced by Melissa Gorga and Kathy Wakile beginning in the third season. In the sixth season, Caroline Manzo departed the series while Laurita and Wakile transitioned into supporting capacities; their original positions were filled by the returning Dina Manzo and new housewives Teresa Aprea, Amber Marchese, and Nicole Napolitano.
The current cast, from left: Marchese, Manzo, Gorga, Giudice, Napolitano, and Aprea.
The Real Housewives of New Jersey was first announced when Bravo released its 2008–09 programming on April 15, 2008. It was later announced that the series would debut on May 12, 2009, with Caroline Manzo, Jacqueline Laurita, Teresa Giudice, Dina Manzo, and Danielle Staub as the cast. For the first time in the franchise, the series followed housewives who are related to one another: sisters Caroline and Dina are married to brothers Albert and Tommy Manzo, and Jacqueline Laurita is married to Caroline and Dina's brother, Chris Laurita. Dina and Tommy Manzo would later end up divorced. With the first season averaging 2.55 million total viewers, Bravo announced the renewal of the second season on October 6, 2009. The second season premiered on May 3, 2010, with Dina Manzo departing the series after the seventh episode of the season. Part 1 of the second season reunion gathered 3.9 million viewers, making it the highest-rated episode of the season — at the time — of its airing and the second highest rated episode of the franchise after the January 30, 2011, episode of The Real Housewives of Atlanta. Both of these milestones would be surpassed in future seasons or by fellow Real Housewives series.
The third season renewal was announced on August 31, 2010. It was later revealed on September 7, 2010, that Danielle Staub would not returning to the show. Season 3 premiered on May 16, 2011, with a 90-minute episode as well as new housewives Melissa Gorga and Kathy Wakile. The third season delivered the highest rated season premiere in the network's history and the highest rated season premiere in The Real Housewives franchise but was later surpassed by The Real Housewives of Atlanta. After season 3, The Real Housewives of New Jersey was the only The Real Housewives series within the franchise that features a main cast who are all married until The Real Housewives of Miami also met the criteria starting with its third season. Season 4 was announced on June 7, 2011, with the fourth season premiering on April 22, 2012. All of the Season 3 housewives returned. Bravo announced that the fifth season would premiere June 2, 2013, with same cast returning. Kim DePaola and Jennifer Dalton joined the fifth season as a "Friends of the Housewives". The fifth season reunion was filmed on September 4, 2013, and took 15 hours to complete.
On October 13, 2013, Caroline Manzo announced that she would not be returning for the series' sixth season. Jacqueline Laurita also departed the series.  In April 2014, Bravo announced that the sixth season would premiere in mid-2014. For the sixth season, Dina Manzo returned. It had been reported by several news outlets that twins Nicole Napolitano and Teresa Napolitano, and Amber Marchese would be the cast additions for the season. On May 14, 2014, Bravo announced that The Real Housewives of New Jersey would return for its sixth season on July 13, 2014. It was confirmed that Dina Manzo would return with new additions Amber Marchese and twins Teresa Aprea and Nicole Napolitano joining as main housewives. Kathy Wakile was demoted to a recurring role and made numerous appearances during the season as well as took part part in a reunion show. Former housewife Jacqueline Laurita appeared in multiple episodes as well.