Taking advantage of ideal scoring conditions on another glorious morning of sunshine at Riviera Country Club, the 26-year-old Korean birdied his first four holes on the way to a six-under-par 65 and a nine-under total of 133.
Bae, a rookie on the US Tour last year, was joined at the top late in the day by Jacobson, who fired a matching 65 after piling up four birdies in five holes around the turn.
The highlight of the Swede's round was a 55-foot birdie putt from just off the green at the par-four ninth.
"That putt was pretty spectacular," Jacobson, whose only US Tour victory came at the 2011 Travelers Championship, said.
"There were a lot of slopes and bumps along the way to get it there but I managed to trickle it over the edge, so that was a bonus."
Americans John Merrick (66) and John Rollins (65) were tied for third at eight under but several former Major winners and heavyweight players were in hot pursuit.
British world number three Luke Donald was just two shots off the pace after a 66, with 2011 Masters winner Charl Schwartzel (67), US Open champion Webb Simpson (66) and former world number one Lee Westwood (68) a further stroke back.
Twice winner Phil Mickelson (67), Spaniard Sergio Garcia (73), Australian Adam Scott (67) and British Open champion Ernie Els of South Africa (68) were among eight players at four-under 138.
"I played very well today," Bae said after mixing nine birdies with three bogeys on a challenging Riviera layout where there is little margin for error with approach shots into the teasingly small greens.
"I hit a bunch of good shots and I made many good putts, but I missed a couple of short putts on holes number five and seven.
But that was not a big problem. I did my best today."
Bae was a runner-up at last year's Transitions Championship and he knows how difficult it is to win on the US Tour.
"There are many good players on the (US) PGA Tour so it's very competitive," he smiled. "It's a good experience for me and I will just play my game. My goal is to win, but that's not easy."
Winning this week will certainly not be easy for Bae with 12 of the world's top 20 players heading a strong field at Riviera.
Among them is former world number one Donald who has recorded three top-six finishes at the venue in the past five years.
"I'm happy with my score, obviously coming off a pretty good break," said the Englishman who is playing his first tournament since he tied for third at the European Tour's DP World Tour Championship in November.
"You never know how you're going to deal with being back in competition again but certainly a big improvement today, ball-striking wise. My short game has been very sharp.
"I've been excited about that. It's been a big key to my score so far and I'm excited to be in the mix again."
Donald, a five-times champion on the US Tour, totalled only 25 putts on Friday and sank monster birdie putts from just off the fringe at the third, from 22 feet, and at the fourth, from 72 feet.
Overnight leader Matt Kuchar, who opened with a 64 to take a one-stroke lead, slipped back with a 73 to end the day four strokes off the pace, level with defending champion Bill Haas (67).
The cut fell at two-over 144 with triple Major winner Padraig Harrington of Ireland, Masters champion Bubba Watson and 2010 US Open winner Graeme McDowell among those failing to advance.