Work started on the playground on June 12, 1948. All men in the community were encouraged to pitch in. "We must take some action toward providing the children of Chelsea Park with diversion." Mr. R. Fordham directed the crews who came to work. More than a dozen men cut down trees, burned brush, and did the groundwork for establishing the playfield. Many children, "evidencing their eagerness for this desirable manner and place to spend vacation days, were on the job to do whatever they could to help." Men were requested to work every Saturday morning, "to make this long-sought project become a reality." It was hoped that "a place sufficiently interesting and healthful can be developed to entertain our youngsters during vacation and keep them from crossing these three lanes of very rapid traffic." (Highline Times, June 17, 1948)
Ground for the playfield was broken on January 6, 1949 by the South Seattle Excavating Company, after two years of effort by the Chelsea Park Community Club. Some of the remaining stumps were blasted out. The names of contributors were published in the Highline Times. As of January 27, 1949, $52 had been raised toward the expected cost of $500 to finish clearing and leveling the land.
Later that year, construction was begun on an amusement center for children and adults, with an outdoor dancing deck. The wooded area was cleared for $1,100. The King County Parks and Playfields Board assisted, along with a generous donation of work by the South Seattle Excavating Company.
The park land, known as Chelsea Park #42, was deeded to the county on May 31, 1951. It was a gift conveyance ($10) from Desmond Peck and Clarence Hardesty, trustees of Northwest Homes, Inc. The Chelsea-Evansvale Community Club had donated their services through labor to prepare and grade the land, and raised funds for playground equipment. In April 1953, the Club petitioned the King County Parks and Playground Department to install proper drainage and grading, erect suitable buildings for shelter, and incorporate the playground into their schedule for supervision of youth activities.
In February 1968, King County voters approved Proposition 6, a Forward Thrust Parks and Recreation bond, which included $21,750 for a Chelsea Park playground.
In January 2000, King County offered Burien assistance in replacing the backstop, and providing new fences, dugouts, and concrete floors. Chelsea Park has been the site of countless baseball, softball, and soccer games - both organized and informal - throughout its 56-year lifespan.