On December 15, 2018, the Office of Legacy Management celebrates 15 years. On this date in 2003, the office was formally established as a new element within the Department of Energy when personnel from four different organizations were merged into a cohesive organization.

LM was charged with responsibility for ensuring that DOE's post-closure responsibilities are met and for providing DOE programs for long-term surveillance and maintenance, records management, workforce restructuring and benefits continuity, property management, land-use planning, and community assistance. The office currently oversees 92 sites, a number that is projected to grow to 122 by 2030.