The company was founded in 1957 as Allied Security, and in 2016 was merged with Santa Ana, California-based security and janitorial services company Universal Services of America to form Allied Universal.

[6] In 2004 and again in 2008, Allied Barton bid but failed to acquire M & M Investigations & Enforcement Bureau of Toledo, Ohio.

In 2006, AlliedBarton acquired San Antonio, Texas-based manned guarding firm Initial Security for $73.6 million.

[8] In July 2015, Paris, France-based private investment firm Wendel acquired AlliedBarton from The Blackstone Group for US$1.67 billion.

After the merger, Allied Universal was considered the largest security company in North America.