Democratic Senator Debbie Stabenow was re-elected to a fourth term, defeating Detroit businessman and Army veteran Republican John James.
Stabenow had seen the race tighten in the final days of the campaign. She faced a strong competitor in James, who would have become the second African-American Republican in the current Senate if he had won.
Stabenow campaigned as a pragmatic lawmaker who forges bipartisan agreement despite the partisan rancor in Washington. She cited her work shaping farm legislation and pushing a new law that allows pharmacists to tell consumers when they can save on prescriptions by paying cash instead of using insurance.
The 68-year-old Stabenow, of Lansing, criticized Trump's attempt to slash federal funding for the Great Lakes. She said James would have been an unabashed enthusiast of President Donald Trump with no governing experience.
Trump won Michigan in 2016 and called James, a black combat veteran and business executive, "a star" candidate.
Former President Obama stumped for Stabenow and other Democratic candidates in the final stretch of the race in a reflection of the high stakes for the Democratic Party.