chief secretary; secretary-general
A senior executive role in a political party, responsible for day-to-day operations and strategy. In Japan, most commonly associated with the Liberal Democratic Party's 幹事長.
The LDP's secretary-general held a press conference.
He assumed the post of party chief secretary.
書記長 is also translated as secretary-general, but is more common in labor unions, communist parties, or international organizations. 幹事長 is the standard term for mainstream Japanese political parties.
Compound of 幹事 (kanji, 'secretary' or 'organizer') and 長 (chō, 'chief' or 'head').