The memorandum is one of the most far-reaching executive actions by the president this year. New rules would likely not take effect until 2015.
Obama has pledged that when necessary, he will bypass Congress to act on his own on economic initiatives.
Advocates of new overtime rules say millions of workers could benefit. Critics say it could overburden small businesses and other companies and actually cost jobs.
Obama has focused this year on increasing worker pay. He's calling on Congress to increase the federal minimum wage from $7.25 an hour to $10.10.