"We really fed off of (Harrison) today," Young said. "Usually when you have a good offensive performance you feed off the starting pitcher."
Harrison (14-7) pitched eight strong innings to match his career high for wins, set last season. The left-hander allowed two runs and two hits, struck out seven and walked one.
"Tremendous," Rangers manager Ron Washington said of Harrison. "He worked fast, he got quick outs, he pounded the strike zone, he used all his pitches."
David Murphy also connected and doubled twice, and Geovany Soto had three hits as baseball's highest scoring team passed 600 runs for the season. The AL West leaders sit atop the majors with 606 runs scored.
"Offense is always a hot-button issue in Texas with the culture we've built up with offense over the years," Young said, "but we're no different than any other team in the sense that starting pitching is always the biggest key. We get that kind of effort, we like our chances."
Held to four runs while splitting the first two games of the series, Texas pounded out 19 hits in the finale, two shy of their season high.
Harrison entered with an 0-2 record and a 12.00 ERA in five career games against Toronto, including a loss May 2 at Rogers Centre when he allowed a season-high eight runs in 3 1-3 innings.
A slight tweak to his windup didn't deliver results in the bullpen, but things came together once Harrison took the mound.
"I kind of turned more toward first base out of my windup," Harrison said. "I was having trouble staying over the rubber and this helped out a lot."
"I was a little worried warming up today because I was all over the place," he added. "I probably threw 20 balls in the dirt. It ended up working out so I can stick with it."
Harrison became the first lefty in Rangers history to win 10 road starts in a season. He's 10-4 in 15 outings away from home, including two shutouts.
"The most important thing was my mechanics and I was able to hone those in pretty quick," he said. "It definitely kept me in the strike zone more and built confidence, and I was able to be more aggressive with all my pitches."
Young's fourth homer in the fifth gave him as many RBIs with one swing as he had collected in 17 previous games in August. The drive also snapped a career-long 88-game drought between home runs. Young last went deep in a win May 7 at Baltimore.
"I saw him use his hands the way he's able to," Washington said. "Before he had a lot of body and today it was hands. Hopefully he's about to come around."
Murphy went 3 for 4 with a walk and hit a solo drive in the ninth against rookie Chad Jenkins for his 11th homer of the season. Mark Lowe completed the two-hitter as Texas won for the third time in four games.
"David has been swinging the bat extremely well," Washington said of Murphy.
Mike McCoy hit a solo homer and drove in two runs as the Blue Jays lost for the 16th time in 21 games. Toronto went 3-7 on a 10-game homestand against the AL's three division leaders, New York, Chicago and Texas.
"(Texas) is a team you can't make mistakes against," Blue Jays catcher Yan Gomes said. "One through nine they can hurt you."
Trailing 1-0 on McCoy's groundout, Texas took the lead in the third when Soto and Mitch Moreland hit back-to-back RBI singles.
Murphy doubled home Young in the fourth before the Rangers pulled away with a five-run, 10-batter fifth. Josh Hamilton hit an RBI double, Nelson Cruz singled home a run and Young whacked a first-pitch homer to center.
Most of the damage came off Henderson Alvarez, who allowed career highs of eight runs and 12 hits in 4 1-3 innings and lost his fourth straight start. Alvarez (7-11) is winless since July 28 against Detroit.
"I didn't think he used his secondary stuff enough, particularly as they started to be aggressive early in the counts," Blue Jays manager John Farrell said of Alvarez.
Alvarez fell to 3-8 in 13 home starts and declined to speak to reporters, citing a death in his family.
Told what his mound opponent had been dealing with, Harrison extended his condolences.
"I'll say a little prayer for his family and him tonight," Harrison said. "That's pretty tough. To have that on your mind when you go out and pitch, your focus is definitely not on pitching."
McCoy hit his first homer in the fifth, but Texas made it 10-2 in the sixth when Young hit a two-run double off Brad Lincoln. Young's five RBIs was a season high.
NOTES: The Rangers had a season-high 21 hits on April 17 at Boston. ... Harrison has now beaten every AL opponent at least once. ... Rangers 2B Ian Kinsler snapped an 0-for-21 slump with a double in the third. ... Blue Jays 1B David Cooper (lower back tightness) was scratched. Edwin Encarnacion moved from DH to first and Jeff Mathis took over at DH. ... Rangers RHP Koji Uehara (strained muscle in his right side) threw a 30-pitch session of live batting practice at Double-A Frisco on Saturday. Uehara will make a rehab appearance with Triple-A Round Rock on Tuesday. ... Toronto's Adeiny Hechavarria made his first career start at second base. ... Gomes was optioned to Triple-A Las Vegas following the game. Toronto will make a corresponding move before Tuesday's game at Detroit. ... 3B Brett Lawrie (strained right ribcage) went 0 for 3 and struck out once in a rehab game at Class-A Dunedin ... RHP Brandon Morrow (strained muscle in left side) gave up two runs and four hits in 4 2-3 innings of a rehab start at Double-A New Hampshire. Morrow threw 81 pitches, walked two and struck out four.