Dedicated in January 1978, Brentwood Park began with 1.5 acres. It sat adjacent to the site of a K-8 private day school (Park School) that served over one hundred students per year and operated through 2006, when Park Private Day School closed its door permanently.

On March 16, 2007, the City purchased the property at 261 Monte Vista Avenue, for the purpose of expanding the park, which resulted in a total of 2.64 acres of park space.

The facility included an on-site 12 space parking lot, an office building, 12 classrooms, 6 restrooms, and a pool. Upon inspection of the newly acquired property staff identified a number of costly repairs, which were needed in order to bring the site and its facilities to current code. The City Council determined it would be more cost effective to demolish the facilities than to restore them to reuse. The demolition work was completed in July 2008.

The acquisition of the Park School land caused the need for the development of a Master Plan for Brentwood Park.

The City worked with the community to develop the proposed Master Plan concepts that identify preferred current and future uses for Brentwood Park.

Funding in the amount of $460,000 for the master planning and design of the project was approved with the adoption of the 2007-2008 Capital Improvement Program budget.

In 2009, the Costa Mesa City Council approved Brentwood Park’s Master Plan but voted to keep the park free of basketball and tennis courts.

In 2011, in a statewide competition for grant funding, the Office of Grants and Local Services of the State of California Parks Department awarded Costa Mesa $275,000 to develop Brentwood Park.

In January 2014, construction of the Master Plan was scheduled to commence.

Then, sometime in 2014, City Council members conflicted on the use of the state grant money for Brentwood Park, with some members desiring the grant money to go to Westside park development. The grant money, however, was awarded to the city specifically by the Land and Water Conservation Fund Program for Brentwood Park. The city was then forced to return the grant money to the state.