The leaders played two different courses on Thursday. Toms was at La Quinta Country Club, while Villegas played on the Nicklaus Private course at PGA West. Those two courses, along with the Palmer Private course at PGA West, will host the opening three rounds, before the final round is contested on the Palmer course.
Ben Crane is among seven players that share seventh place at seven-under 65.
This is the first time since 1964 that Bob Hope's name isn't associated with the tournament, though his name remains on the trophy. Former President Bill Clinton has added his name to the tournament and brought in a few big names to re-invigorate the event.
Clinton will play alongside Norman in the pro-am portion of the event on Saturday.
Toms played the front nine first and opened with four straight pars. He turned it on from there as he birdied the next four holes to jump up the leaderboard.
The 45-year-old Toms birdied the 10th, then dropped in back-to-back birdie chances from the 12th to move to minus-seven.
Toms converted birdied chances at 16 and 18 to grab a piece of the lead.
"I struck the ball pretty well all day. I didn't make any putts the first few holes and I had some great looks, then all of a sudden I made a long one, and then I made a couple after that," Toms said in a televised interview. "Then, for the most part, just played solid golf.
"I was never really in trouble off the tee. I hit a lot of greens, had a lot of looks and putted well."
Villegas played the back nine of the Nicklaus course first, and opened with birdies on each of his first two holes. After a pair of pars, he drained three straight birdie chances from the 14th.
The Colombian made the turn at five-under. He birdied three of the first four holes on the front nine. Villegas parred the next three holes, then birdied the par-five eighth to end at minus-nine.
"A great day out there. Obviously, the weather is beautiful, golf course conditions are perfect and I had a great group," Villegas said. "We had some laughs out there and felt pretty relaxed. It's a really nice way to start the year. I kept the ball in play, made a lot of great putts and then again had a lot of fun out there."
Johnson Wagner, last week's winner at the Sony Open, carded a four-under 68 on the Palmer course and is tied for 31st. Defending champion Jhonattan Vegas is tied for 80th at minus-two after a round with five birdies and three bogeys.
NOTES: There 12 former champions in the field including Vegas and Mickelson...Tops among that group is Pat Perez, who opened with a five-under 67 at La Quinta...Toms, who played alongside Mickelson, will shift to the Nicklaus course on Friday, while Villegas will play the Palmer course.