Unperturbed by the wind swirling in Arthur Ashe Stadium, Williams took another step toward a third straight title in Flushing Meadows.
The only woman to win at three straight US titles in the Open era was Chris Evert, who won four from 1975-78.
Williams needed just 56 minutes to dismantle the 25-year-old, 81st-ranked King, but insisted it wasn't easy.
"It's so hard to play in the wind," said Williams, who nevertheless came up with 25 winners against 15 unforced errors in the 56-minute contest.
Three of her five double faults came in her first service game of the match as she adjusted to the conditions.
"Especially one side's a little harder, it makes your serve different," she said. "Getting through that game was really important. You have to be able to adjust."
Although Williams has won five WTA titles this year, 2014 has been a substandard season in terms of Grand Slam results.
She has not only failed to add to her 17 Grand Slam titles, she has failed to get past the fourth round at any of the year's three prior majors.
She'll try to take another step toward filling that gap on her season record when she faces her third straight American opponent, Varvara Lepchenko, for a place in the last 16.