Porter fired a 7-under-par 65 in the weather-delayed second round of the Touchstone Energy Tucson Open to take a two-shot lead over a trio of others through 36 holes.
At 10-under-par, Porter is leading 1994 Tucson champion Andrew Magee, '96 U.S. Open champion Steve Jones and Mark Wiebe, who are all at 8-under 136. Magee and Jones each carded 66 on Saturday at the Gallery course, where snow fell Friday to force a postponement of play, while Wiebe came home in 67 strokes.
Porter is a veteran of the Japanese, European, Asian, South American, Canadian and Buy.com tours. The 34-year-old has made 44 cuts in 123 previous PGA Tour starts, and now finds himself in unfamiliar territory.
'I've never led on this tour,' said Porter, who carded seven birdies and no bogeys in his second round. 'I've led in events around the world. I've played just about everywhere there is to play, and I think I was in second place at the U.S. Open one year going into the third round. It's a new position for me, but you've got to be there sometime.'
Bernhard Langer and Mark Hensby are three shots back of Porter at 7-under-par. Langer, a two-time Masters champion, followed a first-round 68 with a second-round 69.
'I feel fairly good,' Langer said. 'I've got to work on my driving a little bit. I wasn't totally happy with my driver; that's why I hit a number of 3-woods.'
Of the six first-round leaders, only two remain in the top 10. Geoff Ogilvy and Kevin Sutherland are in a ten-way tie for 10th place at 5-under, after shooting a pair of even-par 72s.
Tim Clark dropped from a tie for first into a tie for 20th following a second-round 73. Willie Wood is tied for 46th after a 75; while Glen Day and Tim Herron shot 76 to fall into a tie for 55th.
Eighty-three players made the 144-cutline. Among those who failed to qualify for the final two rounds were Curtis Strange (145), Lee Janzen (147), Gary Nicklaus (150), Casey Martin (150) and Craig Stadler (151).
The third and fourth rounds will be contested on the Tucson National course. The final round will be played on Monday.
Click here for Full-Field scores from The Tucson Open!