Former NHL All-Star Jeremy Roenick and ex-quarterback Chris Chandler were tied for second at Edgewood Tahoe Golf Course.
Others in the hunt included hockey's Mike Modano and Brett Hull, Dallas Cowboys quarterback Tony Romo and former pitcher Rick Rhoden, who has won the event a record eight times.
Five years ago, Wagner became the only non-professional athlete to win in the tournament's 22-year history. He had seven birdies Friday for a total of 29 points in the modified Stableford scoring system. He shot a 3-under 69 in a regular format.
"The great part about this event is we've kicked around together for 20-some years now," said Wagner, who tied for second last year and has finished outside the top 10 only five times in 21 previous appearances.
"I think these guys kind of like that they have a little pip-squeak actor they can play with," he said. "Someone who is a little different who can actually hit it kind of out there with them, though not near as far."
"These guys hit it like Bubba Watson and Dustin Johnson. They actually are that explosive," Wagner said.
Roenick rolled home a 40-foot eagle putt on the par-5 18th to vault into a tie for second with 24 points in the scoring system that awards six points for eagle, three for birdie, one for par, none for bogey and minus-2 for double bogey or worse.
Modano finished the day with 20 points, followed by Hull, Romo and Rhoden all with 19. John Smoltz had 18, followed by Vinny Del Negro, Brett Saberhagen, Vince Coleman and Tim Brown at 17. Michael Jordan had 16.
Roenick said Rhoden is capable of putting up 30 points in a single round, but that Wagner is playing solid.
"I've got to try to get into Jack's head a little bit tomorrow and let him know the athletes are coming after him," Roenick said. "Mentally he is a grinder, but physically, maybe, hopefully we'll roll around in the sand a little bit tomorrow."
Wagner shot back, "I'll kill him with my outfit. It's about what you wear, dudes."
As usual, some of the biggest fan interest was at the bottom of the leaderboard where former NBA MVP Charles Barkley and actor Kevin Nealon entertained the gallery more with one-liners than their golf.
"Come on Charles, get it off the tee box," Nealon encouraged his playing partner on the par-3 No. 7.
He didn't. It went about 10 yards. But Barkley's next swing - a one-handed six iron - sent the ball 160 yards to the fringe of the green to loud cheers.
Nealon knocked his next shot only a few feet into a greenside sand trap, so it was Barkley's turn to needle.
"Anybody have a half of a Snickers bar?" he asked the crowd as he waited for Nealon to try again.
Another big group was following a trio of actors - Ray Romano, Dennis Haysbert and Brian Baumgartner - although at least one fan didn't know who all of them were.
As they waited to tee off on No. 18, the man mistook Haysbert for Jordan and yelled, "Michael, basketball has not been the same since you retired."
It drew a laugh from players and observers alike. Then, as Baumgartner - who plays the portly Kevin on NBC's "The Office" - prepared to hit his drive, Romano shouted at him: "Same to you Larry Bird."
