Aberg, who burst on to the professional scene with a PGA Tour win and debut Ryder Cup success last year, already looks a natural on the biggest stages.
Having finished runner-up in his first major at the Masters in April, Aberg led at halfway in the US Open last month and will make his Open debut at Royal Troon next week.
He was nonchalance personified as he matched his opening round in East Lothian.
With conditions once again favourable, the Swede made hay as the sun shone, picking up strokes on 11 – his second hole – and 14 before superseding Im at the top of the leaderboard with back-to-back birdies on 16 and 17.
Two more followed on the par-five third and short fifth when Aberg splashed out of bunkers each time and rolled in the putts.
“I wouldn’t describe myself as a superstar – all I try to do is play good golf,” he said.
“Whether these last 12 months have changed my life on the golf course, it hasn’t changed my life off the course. I’m still the same personality.
“Any time you shoot 64, it’s a good day. We handled the golf course very well and never tried to force anything.”
Im had come tearing out of the blocks with birdies in half of his first six holes to set the early pace, but a three-putt bogey on the first checked his momentum before he gained a stroke to return to 10 under.