From 1994 to 2000, she served as an executive assistant United States attorney in the Eastern District of Michigan.

[6] In December 2020, Parker heard a lawsuit brought by attorneys for then-president Donald Trump, attempting to reverse the Michigan results for the 2020 U.S. presidential election, one of the so-called "Kraken" suits.

She dismissed the suit, saying it was full of "theories, conjecture and speculation" and adding that "the people of Michigan have spoken.

"[7] In July 2021, Parker ordered all the attorneys who had argued Trump's case to appear before her, as she considered motions filed to impose sanctions on the attorneys for arguing that Trump had won the election and presenting evidence that she said they had not evaluated for accuracy.

[8] On August 25, 2021, Parker ruled that "Plaintiffs' counsel filed this lawsuit in bad faith and for an improper purpose", demanding that the attorneys, including Sidney Powell and Lin Wood, pay the legal fees of some of the defendants in the suit, and that they be referred to their respective state bars for disciplinary action.