Former Montgomery County Executive Doug Duncan filed papers Monday to run for the county's chief executive post, reports CBS DC.
Duncan, 58, a Democrat, left the office after 12 years to run for governor in 2006, but he withdrew from the race when he was diagnosed with depression.
He will be running in a June 24 primary. Democratic incumbent Isiah Leggett has announced he will seek a third term as county executive.
Montgomery County Councilman Phil Andrews also has announced he will run.
According to a state website, Duncan was the mayor of Rockville from 1987-1993 and more recently served as the vice president for administrative affairs at the University of Maryland, College Park, in 2007 and 2008.