Scott Walker Recall Petitions Filed
Gov Walker was the focus of protests in 2011 after he and state Republicans curbed public sector unions’ rights.
He could face the recall election by this summer if the minimum 540,208 signatures are verified.
The governor has become a conservative hero and put the Midwest state at the centre of the US labour rights debate.
Organisers from United Wisconsin submitted about one million signatures on Tuesday.
Two Republican state senators were recalled in earlier elections.
A recall effort could not be officially filed until Gov Walker served a year in office, which happened earlier this month.