Franken, 53, gained fame as a writer-performer on "Saturday Night Live" and has not lived in Minnesota for more than 30 years.
He told the Minneapolis Star Tribune he would divide his time between Minnesota and his current home in New York until next year, when he plans to move his three-hour daily radio show on the Air America network to the Twin Cities.
Franken has spent the past 18 months debating running for the U.S. Senate seat once held by late Democratic Sen. Paul Wellstone, who died in a plane crash in 2002. Republican Norm Coleman defeated former Vice President Walter Mondale to win the seat.
Franken and his wife bought a townhouse near downtown last month.
"It's one of the things I need to do if I decide to make a run," Franken said. "I haven't made a decision yet, but if I do, I'll have to have been living in Minnesota for a while."