Kucinich, the former mayor of Cleveland, filed papers in Columbus on Monday to establish a campaign committee.
Kucinich, 71, launched his political career almost 50 years ago when he served on the Cleveland City Council and later captured the mayor's office in 1977.
The gubernatorial race is already crowded with candidates for both parties.
Kucinich lost the congressional seat he first won in 1996 in 2012, following redistricting that put two Democratic incumbents in the same district.
Mr. Cordray's announcement will come shortly before Republican Lt. Gov. Mary Taylor is expected to announce Cincinnati area business executive Nathan Estruth as her running mate.
Cordray entered the race last month and Ohio Supreme Court Justice William O'Neill has announced plans to leave the bench this month to also make a run for the Democratic nomination.
The candidates are reaching crunch time to finalize their tickets in order to circulate the nominating petitions they must file by February 7 to officially become candidates.
The 71-year-old Kucinich served in Congress from 1997 to 2013.
Samsung MicroLED makes massive, 146-inch modular TV a reality
While that phrase sounds like typical PR/marketing hyperbole, we are actually inclined to trust Samsung's diagnosis in this case. Samsung's decision to bet on micro-LED puts it in direct competition with rivals that have opted to go with OLED displays.