Republican Senate candidate Herschel Walker has sprinted out of the blocks when it comes to fundraising for his Senate campaign to try and unseat Democratic Sen. Raphael Warnock of Georgia in the 2022 midterm elections.

The former professional and college football star running back, who won a Heisman Trophy and helped propel the University of Georgia to a national championship, announced Monday that his campaign pulled in $3.7 million — or about $100,000 per day — from his late August launch through the close of September, which marked the end of the third quarter of fundraising.

Walker,...