Unlike many NBA arenas with sleek modern architecture, Gainbridge Fieldhouse, originally named Conseco Fieldhouse, was designed with an intentional retro style. Ellerbe Becket, an independent Minneapolis-based architectural, engineering, interior design, and construction firm designed a building that reflected typical high school fieldhouses in Indiana for the Indiana Pacers, whose home at Market Square Arena was deteriorating and outdated.

Construction began in July 1997 and was finished two years later. At a cost of $183 million, the Pacers organization contributed $57 million, $79 million came from taxes, and the remainder came from private contributors. It opened at 125 S. Pennsylvania Street on November 6, 1999, as one of five new NBA arenas that opened during the 1999-2000 season.

The arena truly resembles a classic basketball fieldhouse. Its façade consists of brick and glass, congruent in style with surrounding buildings in downtown Indianapolis. The nostalgic look continues to the interior as fans enter through the Entry Pavilion, the main gathering place before and after games. Fans take the Grand Staircase to the different levels of the arena. The seating capacity of 18,345 includes 69 luxury suites and 2,400 club clubs. The Founders Level is regarded as having the best seats with 16 rows radiating from the court into the arena.

In December 2011, the arena was renamed Bankers Life Fieldhouse after CNO Financial purchased Conseco. The arena has consistently been recognized as one of the top in the NBA.

The Fieldhouse is home not only to the Pacers but also to the WNBA Indiana Fever. Though primarily designed for basketball, Bankers Life hosts indoor concerts and ice hockey. To accommodate the NHL-sized ice hockey rink seating capacity is reduced to 12,500 in an asymmetrical configuration.

On March 13, 2018, the Fieldhouse announced that CNO had decided not to renew its naming sponsorship which expired June 30, 2019. The 20-year deal had been worth about $2 million per year.

A $400 million renovation to the venue began in April 2019. Phase one of the three-phase renovation project started in the summer of 2020 and was finished before the NCAA Tournament in 2021. The first phase focused exclusively on interior renovations.

These updates include improvements to visitor locker rooms, renovations to the Lightbound Courtside Club, 2 new sideline clubs, and a handful of changes to the KeyBank Level including 10 new suites and 2 loge clubs. The alterations reduced the number of suites from 64 to 56.

Conference rooms and the media workroom were updated. The practice court was moved up one level to accommodate the relocation of the Indiana Fever locker room to that space.

Phase two and three renovations included exterior enhancements. Demolition of the parking garage, necessary for the new outdoor entry plaza, began in March 2021. Almost all construction took place during the Pacers’ off-seasons. The Fever was displaced to the Butler University Hinkle Fieldhouse for both the 2020 and 2021 seasons, and part of the 2022 season.

As part of the renovation agreement, the Pacers agreed to remain in Indianapolis for at least another 25 years. Indianapolis’ Capital Improvement Board owns the fieldhouse and plans to use the renovations as a marketing opportunity for the arena’s new name, Gainbridge Fieldhouse. The new name came with a partnership between the Pacers Sports & Entertainment and Gainbridge, an Indianapolis-based online financial services platform.

The target completion date for all renovations was early 2023, but because of delays due to the COVID pandemic, Bicentennial Unity Plaza, the final piece of the $400 million renovation, did not open until late August 2023.

Bicentennial Unity Plaza includes a $30 million mix of sculptures, art, and a basketball court, which will be transformed into an ice skating rink larger than the one at Rockefeller Plaza in New York City during winter months. The Arts Council of Indianapolis partnered with Pacer Sports & Entertainiment to create a Unity Plaza Bicentennial Legends Mural. The plaza is intended to recognize the 200-year history of Indianapolis while looking forward. In addition to being a place for pregame parties, the sports corporation wants the plaza to be used all year to host basketball tournaments, farmers markets, sunrise yoga, and many other activities.