Brookdale Senior Living is the largest owner and operator of senior living communities throughout the United States, operating over 1,100 senior living communities and retirement communities in the US.

Brookdale was established in 1978 and is based in Brentwood, Tennessee. In the late 1990s and early 2000s, Fortress Investments became the majority owner of Brookdale, holding approximately 51% of its share. Brookdale has approximately 80,000 staff members and 100,000 residents.

Brookdale offers Independent Living, Personalized Assisted Living, Memory Care for Alzheimer's disease and dementia diagnosed residents, Rehabilitation, Skilled Nursing and Home Health Services. Brookdale also offers Continuing Care Retirement Communities where residents can live without moving when they need nursing care.

Brookdale started its business with a focus on large upscale urban retirement communities located in large cities such as Chicago, New York, and Miami. These early models replicated five-star hotels like the Hyatt, Marriott's, and Hilton hotels of the modern era.

Throughout the late 1990s and early to mid-2000s, Brookdale developed several more communities that resembled earlier models, but also reflected the changing retirement trends. These new communities included Continuous Care Retirement Communities (CCRC), which house skilled nursing facilities, assisted living, independent living, and memory care facilities.

By early 2005, Brookdale had grown to approximately 90 standalone properties. During this time Fortress Investments acquired the recently bankrupt Alterra Corporation Atlerra exited bankruptcy with approximately 300 properties. This property was merged with Brookdale.

In July 2006, Brookdale announced its merger with the American Retirement Corporation (ARC Therapy). ARC operated approximately 130 properties. Fortress saw this as an opportunity to put Brookdale at the forefront of senior living, not just by sheer size but with the marrying of two of the longest-running and most successful companies in the industry. After the ARC merger, Brookdale was operating approximately 550 communities in 36 states.

In October 2009, the Wall Street Journal reported that Brookdale was buying 21 free standing properties from Sunrise Senior Living Services to acquire.

In October 2011, Brookdale agreed to acquire Horizon Bay Retirement Living, a privately-held company with approximately 90 communities.

In July 2014, Brookdale merged with Emeritus Senior Living. The merger transformed Brookdale into the only national full-spectrum senior living solutions company, with over 1,100 communities in 46 states, covering 80% of the U.S. population.

In 2013, a Brookdale facility, Glenwood Gardens in Bakersfield, California, became the focus of national media coverage when a staff member refused to give CPR, as requested by a 911 operator, to 87-year-old Loraine Bayless, a resident. Lorraine died at Glenwood of a stroke.

After Lorraine's death, Brookdale cited a policy to reporters that allegedly prohibited staff members performing CPR on residents of its independent living facilities; however, the spokesman did not provide copies of the policy to reporters. Brookdale later reversed its public position, saying that the staff member had misinterpreted the CPR policy.

Police closed the Glenwood investigation without filing any criminal charges. The Bayless family said it had no intention of suing Brookdale over Lorraine's death.