Playing her first top-level singles final, the 20-year-old Kenin took the first set with a break before running away with the match in 71 minutes.
Kenin, ranked 56th, didn't drop a set for the tournament and beat top-seeded Caroline Garcia and former Hobart champion Alize Cornet in her run to the title.
She joined compatriot Tennys Sandgren, who won his first ATP Tour singles title Saturday, beating Cameron Norrie 6-4, 6-2 in the final of the ASB Classic across the Tasman Sea at Auckland, New Zealand, as a first-time tour winner.
Kenin saved eight break points early in the first set and found her groundstroke range as the match continued.
"I didn't want to overthink it and I'm happy with the way I composed myself," she said.
The win is expected to move her inside the top 40 for the first time.
Moscow-born Kenin plays qualifier Veronika Kudermetova in the opening round of the Australian Open in Melbourne before a potential second-round match against No. 1 Simona Halep.
Kenin also won the Auckland doubles title with Eugenie Bouchard last week.
"I couldn't ask for a better start," Kenin said.
Kickoff each day of the 2019 Australian Open with Tennis Channel Live, reviewing the day's most important news and previewing the day's biggest matches. Watch LIVE at 6 p.m. ET.
Follow the Australian Open even closer with Tennis Channel PLUS. Go to BuyTCPlus.com and subscribe now!