Miguel Andujar added four hits and an RBI for the Yankees, who took the four-game series 3-1, the first series loss this season for the Blue Jays.
Teoscar Hernandez had two hits for Toronto, including a home run.
Severino (4-1) allowed one run, three hits, two walks, a hit batter and had six strikeouts.
Severino also beat the Blue Jays on Opening Day in Toronto March 29, allowing one hit and striking out seven in 5 2/3 shutout innings.
Toronto left-hander Jaime Garcia (2-1) took the loss Sunday, allowing four runs, six hits and three walks while striking out six in 5 1/3 innings.
The Yankees took a 1-0 lead in the first on the sixth homer of the season by Gregorius, a drive to right on a 1-1 two-seam fastball.
Romine's second-inning double scored Gary Sanchez, who reached on a walk, and Andujar, who doubled and has an extra-base hit in six straight games.
Hernandez hit a 3-2 slider to left center for his third homer of the season with one out in the sixth to trim the lead to 3-1. It was the first homer of the season allowed by Severino.
The Yankees regained their three-run lead in the bottom of the sixth. Garcia was replaced by Seung Hwan Oh with one out after a double by Sanchez and a single by Tyler Austin put runners at the corners. Andujar greeted Oh with an RBI double.
The Yankees added a run in the seventh. Aaron Hicks singled, stole second, continued to third on catcher Russell Martin's throwing error and scored on a sacrifice fly by Gregorius.
David Robertson pitched around a single in the eighth for New York and Aroldis Chapman pitched around two walks in the ninth.
With their top prospect Gleyber Torres, 21, going 0-for-4 in his major-league debut at second base, the Yankees had a starting lineup of players all under 30 for the first time since Sept. 29, 1989.
--Field Level Media
Toronto | NY Yankees | |
Jaime Garcia | Player | Luis Severino |
Loss | W/L | Win |
5.1 | IP | 7.0 |
6 | Strikeouts | 6 |
6 | Hits | 3 |
6.75 | ERA | 1.29 |
Toronto | NY Yankees | |
Teoscar Hernandez | Player | Miguel Andujar |
2 | Hits | 4 |
1 | RBI | 1 |
1 | HR | 0 |
5 | TB | 6 |
.500 | Avg | 1.000 |
Team | Hits | HR | TB | Avg | LOB | K | RBI | BB | SB | Errors |
Toronto | 4 | 1 | 8 | .133 | 16 | 8 | 1 | 4 | 1 | 1 |
NY Yankees | 9 | 1 | 16 | .290 | 13 | 6 | 5 | 3 | 1 | 0 |