Harris completed 24 of 27 pass attempts for 347 yards in Toronto's home-opener far from home in Fort McMurray, Alta.
The 29-year-old threw touchdown passes to Brandon Whitaker, Vidal Hazelton and Tori Gurley, as well as a two-point convert throw to Chad Owens.
Harris will be Toronto's starter for the near future. Ray, a three-time Grey Cup champion, began this season on the six-game injured list rehabilitating from off-season shoulder surgery.
Harris said he'd asked for Ray's input prior to just the second start of his CFL career.
"He gave me real simple advice," Harris said. "He just told me to trust my feet and trust my eyes.
"It's my job to keep the ship afloat until he's back."
Harris's 88.9 per cent completion rate was the second-highest in a single game in Argonauts history, according to the team.
Saturday's game was the first regular-season CFL game played at the new SMS Equipment Stadium in Fort McMurray, although the Eskimos played a pre-season game there earlier this month.
That game and Saturday's have been billed as the most northerly CFL games ever played.
Scheduling issues at Rogers Centre and the Pan American Games in Toronto in July will keep the Argonauts on the road. Their first home game isn't until Aug. 8.
So the Argos were the home team Saturday despite the game's proximity to Edmonton 400 kilometres to the southwest.
Edmonton quarterback Mike Reilly was 16-for-28 in passing for 170 yards and was intercepted once. He threw a touchdown pass to Kenny Stafford in the opening quarter, but left the game with just over three minutes remaining with an apparent knee injury.
Backup Matt Nichols completed one of six pass attempts in relief. Eskimos kicker Grant Shaw kicked a field goal and a pair of punt singles.
Both teams contributed to penalty-filled affair with a combined 245 lost yards, but the Eskimos also had five turnovers in the second half.
"Very frustrating because I know we're better than that," Eskimos receiver Adarius Bowman said. "The Argos did a great job for us tonight, but we could have been a lot smarter with some of the decisions we made as a whole."
Toronto kicker Swayze Waters left the game with a quadricep injury late in the first half and did not return.
Veteran receiver Dave Stala, signed by the Argos a week ago, was pressed into kick and punt duties. The 35-year-old has been an emergency kicker before in his career, but not for several seasons.
Stala had 340 punting and kicking yards, including a 43-yard punt single. His successful field goal attempt in the fourth quarter was called back for a time count violation and Stala missed the second attempt from 36 yards.
"I came here as the sixth receiver, but the more you can do . . . I've kicked in the past and they gave me the opportunity," Stala said. "What I did out there was pretty good. I've still got to get better, but it helped the team win a football game."
The temperature for mid-afternoon kickoff was 31. In a nod to the Argos as the home team, the end zones featured Toronto's logo and their player introductions were accompanied by fireworks.
The stadium has 4,354 permanent seats with temporary stands expanding capacity to 15,000 for Saturday's game.
The extra room wasn't required as attendance of 4,900 was well off the 11,800 who came for the pre-season game between Edmonton and the Saskatchewan Roughriders on June 13.
"We were told there wasn't going to be that many people here, so I wasn't concerned about it being a crowd-noise factor against us," Argonauts head coach Scott Milanovich said.
"It was nice because we had a charter (flight), our cheerleaders got to come, we got the nicer locker room here. Parts of it did feel maybe like a home game. For the most part it was another road game, just some place we'd never been before."