Harris ran for three touchdowns, including two in the final 30 minutes, and Emmanuel Arceneaux scored on a 77-yard passing play early in the third quarter as the Lions beat the Edmonton Eskimos 31-21.
Harris scored three rushing touchdowns for the first time in his CFL career.
"It's huge for me," said Harris. "But at the same time, it's all about the team and getting the win."
The Lions (3-1) swept the home-and-home series with the Eskimos (1-3) after downing them a week earlier in Edmonton.
"I'm just happy to get the win especially against a Western opponent (in) back-to-back games," said Harris. "I thought we played well. We were consistent, we sustained drives and when we needed to run the clock down at the end there, the (offensive) line played amazing."
Arceneaux's spectacular touchdown broke a 10-10 tie and sent the Lions on to victory. The Lions bettered the Eskimos in the final 30 minutes for the second straight game after trailing at half-time a week earlier.
"Just coming out in the third quarter, it was the same situation as last week," said Eskimos quarterback Mike Reilly, who completed 12 of 20 passes for a modest 152 yards.
"It turned over into half-time. Generally, when that happens, whoever comes out (strong) in the third quarter, and sets the tempo and sets the tone for the game, is gonna be on the inside track for the win — and B.C. did that again tonight.
"We didn't seem prepared after half-time."
Paul McCallum booted a 37-yard field goal to account for the rest of the B.C. scoring.
Edmonton backup quarterback Kerry Joseph and Fred Stamps, with just over a minute left in the game, scored touchdowns for Edmonton. Kicker Grant Shaw provided the other Eskimo points on two field goals and a 51-yard single off a missed three-pointer.
Reilly, the former B.C. backup who was traded to Edmonton in the off-season, got the Eskimos offence going early after Chris Thompson intercepted a Travis Lulay pass intended for Arceneaux.
The Eskimos opened the scoring with just over five minutes gone in the game as Shaw kicked a 47-yard field goal, giving them a 3-0 lead after the first quarter. But the Lions were able to build a 10-3 lead in the second quarter as McCallum, playing his first game of the season after missing the opening three with a groin injury, succeeded on his lone field-goal attempt and Harris bowled his way 13 yards.
After coming in for an apparent plunge on second down, Edmonton backup QB Joseph ran for a three-yard touchdown late in the second quarter to create suspense heading into the second half. But it was almost all Lions in the final 30 minutes.
"For whatever reason, we just got into more of a groove," said Lulay, who completed 18 of 24 passes for 284 yards.
Arceneaux shook off Thompson's tackle attempt and also stayed in bounds, as the Eskimos defensive back got his arms on him but could not bring him down along the sideline. Lulay said he and Arceneaux, who accumulated 106 yards off just five receptions, had prepared for just such a play.
"We had a (defensive) look, and we had talked about talked about that earlier, if we had that certain coverage, how Manny could release to get some width," said Lulay. "I was ready for him to make the release that he did.
"So I threw a little bit into space, and Manny got the release that he needed. The biggest thing about that play was his ability to break the tackle and make the big play. For him to break the tackle and stay in bounds takes a little bit of strength."
Lulay maintained his hot passing arm later in the third quarter as he was good on all four attempts during a scoring drive that culminated with a Harris one-yard run. Harris set up his own touchdown as he caught a short Lulay pass and gained 24 yards a play earlier, leaping over a defender in a bid to get into the end zone.
Harris thought he had scored, and fireworks went off prematurely, but a replay showed that his knee was out of bounds before he crossed the goal-line. He felt forced to jump after his attempt to spin inside did not go as planned.
"I wish I could have scored on that, because, I think, that would have been a highlight for sure."
He still thrilled fans as he ran a reverse untouched into the end zone, staking B.C. to a 24-10 lead. The Eskimos showed signs of a comeback attempt, but could only pull within a point off Shaw's wide 43-yard field goal attempt.
Then after the Lions ran about three minutes off the clock and a McCallum punt that pinned Edmonton deep in its own territory, Jabar Westerman recorded a rare interception for a defensive lineman. B.C. Westerman enabled B.C. to use up more time before Harris juked and jived four yards for his third touchdown of the night.
Notes — Edmonton third-string quarterback Jonathan Crompton threw 12 yards to Stamps for his touchdown. ... McCallum handled all of the B.C. punting duties after coach Mike Benevides said Hugh O'Neill could punt in certain situations. ... The Lions inducted legendary former coach Don Matthews and quarterback Damon Allen onto their wall of fame at half-time. Matthews guided the Lions to their 1985 Grey Cup title, while Allen called the signals for their 2000 championship squad. The two CFL hall of famers entered the field riding in vintage convertibles. Matthews, 74, who is recuperating from cancer, and Allen received Lions jackets and plaques. The former coach drew the loudest cheers. ... Lions nickleback Korey Banks played in his 150th CFL career game. ... B.C. defensive back Ryan Phillips needs to play two more games for 150 consecutive contests.