21st century
In October 2002, a Costco store opened north of the mall.[27] In 2003, Federated Department Stores rebranded all Lazarus locations as Lazarus-Macy's in order to expand the Macy's name throughout the United States. The dual-branding also introduced several Macy's product lines to the merchandise mix of Lazarus.[28] The same year, both floors of the Galyan's building were expanded, increasing the store size by 20000 sqft;[29] one year later, Galyan's was sold to Dick's Sporting Goods, resulting in the closure of a nearby Dick's Sporting Goods which had only been open for a year.[30] Federated acquired The May Department Stores Company, then the parent company of L. S. Ayres, in 2006 and announced plans to convert most of the May Department Stores brands to Macy's. As part of this, the Lazarus-Macy's store was rebranded again to just Macy's. Castleton Square was one of four malls in Indiana to have both a Macy's and a division of May Department Stores (L. S. Ayres). As a result, Federated chose to maintain the four existing Macy's sites originally Lazarus and close the May Department stores instead. All four L. S. Ayres locations were closed in mid-2006.[31] A year after closure, the building was demolished for a new outdoor concourse featuring Borders Books & Music, an AMC Theatres multiplex, Johnny Rockets, Stir Crazy, Cold Stone Creamery, and H&M.[32][33] Following the closure of Borders in 2011, its space was renovated for the clothing store Forever 21.[34] McAlister's Deli opened at the mall in late 2014.[35]
On May 31, 2018, it was announced that the two-story Sears store would close in September 2018, along with 62 others across the country.[36] At the time of closure, it was the last remaining Sears in Indianapolis.[37] The same year, Macy's announced that the Castleton Square store would be part of its "Growth 50" campaign to add new options for shoppers at some of its more profitable locations. Included in the renovation are new lighting, fitting rooms, and restrooms, expanded furniture departments, dedicated locations for online pickups and returns, and mobile payment options.[38] As of 2019, Castleton Square remains the largest mall in the state of Indiana, with more than 130 stores.[39] The mall was remodeled in early 2025 with new flooring, paint, and signage. In 2025, Hobby Lobby opened in the former Sears shortly after Hobby Lobby opened, Primark announced they would open a store at the mall in 2026. The store is currently under construction.