Donald Trump, seeking to boost momentum in the last days of the presidential election, wired $10 million of his own money into his presidential campaign Friday morning, two advisers said.

The cash infusion will be used to buy $25 million in new TV advertising in key battleground states, the advisers said. With some polls tightening in recent days, the Republican nominee is determined to pull out a win 11 days from now, one aide said.

Mr....