One impeached-and-removed state governor stands out from the pack for sheer vitality and no-holds-barred assaults on his political adversaries.  Governor John Walton of Oklahoma lasted only ten months in office in 1923, but they were action-packed.  Sticking with the highlights:

• A “radical” Democrat with Socialist allies, Walton made his inauguration a people’s celerbration.  More than 160,000 attended and ate barbecue cooked in a mile-long trench.  (Puts the recent Obama soiree into perspective.)  Walton won early adoption of an expansion of farm cooperatives, stronger workers compensation, better warehouse inspection, and the state’s first free textbook law.
• Like other mid-continent governors of his era, he ran into political trouble when he tried to take control of the state university system.  He had to use a military guard to install a new president of Oklahoma A&M.
• The Ku Klux Klan was a powerful force in Oklahoma at the time, with over 100,000 members.  It began an violent campaign of beatings and intimidation of those supporting Governor Walton. 
• In response, the governor placed two counties under martial law and suspended the right of habeas corpus there (a step that the state constitution specifically prohibited).  A National Guard court in Tulsa exposed numerous activities of the Klan.
• In September 1923, Governor Walton pushed anti-KKK legislation on the legislature.  When it became clear that the legislators were lining up against him  Walton — not one to back down — surrounded the state Capitol building with National Guardsmen to prevent the lawmakers from meeting.  Instead, they circulated a petition demanding his impeachment.
• The governor then placed the entire state under martial law, but the gambit did not work.  The legislature did convene and convict Walton eleven articles of impeachment, including abusing his pardon power and unconstitutionally suspending the right of habeas corpus.

Oddly, Walton was not barred from holding state office in the future.  He ran for a number of additional positions over the next fifteen years, but won only a term as the Oklahoma Corporation Commissioner.