She then served four years as a state appellate judge on the District Court of Appeals covering Summit, Wayne, Medina, and Lorain counties.

President George W. Bush nominated Cook to the Sixth Circuit on May 9, 2001 to a seat vacated by Judge Alan Eugene Norris, who assumed senior status on July 1, 2001.

[7] As a Sixth Circuit Judge, she has authored notable opinions on the Fourth Amendment,[8] Voting Rights,[9] and school free speech.

[10] In 2014 Cook voted to uphold gay marriage bans in Michigan, Kentucky, Ohio, and Tennessee in a 2-1 ruling.

[citation needed] O'Connor was eventually replaced with Samuel Alito, although Cook was mentioned as a possible nominee to the high court had Republican John McCain won the 2008 presidential election.