Critics say they couldn't confirm Mary Sexton to the state Board of Oil and Gas Conservation because they worried the former Department of Natural Resources and Conservation director would hinder development.
The Senate rejected Gov. Steve Bullock's nomination of Sexton in a 27-23 vote Wednesday.
Sexton led the DNRC during Gov. Brian Schweitzer's tenure.
Sexton joins a short list of nominees rejected or driven out by the Senate this session.
The chamber previously turned down former U.S. Representative Pat Williams's nomination to the Board of Regents after Williams said the university had recruited "thugs" for its football team.
Fish Wildlife and Parks Commissioner Bob Ream resigned when his nomination to serve another term stalled.
Commissioner of Political Practices Jim Murry also withdrew his nomination during the confirmation process.