As of Wednesday, records showed Obama issued 149 executive orders, 147 from his first term and two this year, The Hill reported Thursday.
Bush issued 173 executive orders through the end of his first term, the American Presidency Project said. President Bill Clinton issued 200 executive orders through his first term.
Comparing Obama's use of executive power to his predecessors is thorny, since such orders are only part of a president's authority arsenal, experts said.
"They're not the only measure of presidential assertion of authority," said Kenneth Mayer, a University of Wisconsin political science professor who studied the presidency extensively. "He's actually been pretty aggressive on a number of fronts."
Obama, Mayer told The Hill, has enacted policy shifts through informal "executive actions" on issues such gun control, immigration and drone strikes overseas.
For example, his 2011 decision to halt the deportations of hundreds of thousands of undocumented immigrants was communicated by memo from Homeland Security Secretary Janet Napolitano.
While Obama isn't the first U.S. president to bypass Congress to exert authority, his actions -- such as the halting of deportations -- have drawn Republican ire.
"He's circumventing Congress with a directive he may not have the authority to execute," Sen. Chuck Grassley, R-Iowa, said when the immigration decision was announced.