Patrick Sheehan collected three birdies, an eagle and no bogeys to finish one shot back at 5-under-par 67 along with David Edwards.
Huston bogeyed his first hole but he recovered with back-to-back birdies starting at the par-4 third. He then hit a 4-wood to five feet for an eagle at the par-5 seventh and added a birdie at the ninth to make the turn at minus-4.
'The eagle on No. 7 got me going,' said Huston, a six-time winner on the PGA Tour.
The 42-year-old birdied the 10th but found trouble with a bogey at the 12th. He got that shot back with a birdie at the 13th but stumbled again with a bogey at the very next hole.
Huston made a late charge and birdied each of his last two holes to join Franco and Tanaka in the lead.
'Overall I'm happy with the way I played,' said Huston. 'Even with three bogeys.'
Franco, a three-time winner on the PGA Tour, picked up his first birdie of the day at the par-4 fourth. He knocked his third shot from the sand at the par-5 fifth within inches of the hole for another birdie and chipped his third shot to eight feet for a birdie at the par-5 seventh to make the turn at 3 under.
'Early putts for par on No. 1 and No. 2 gave me confidence,' said Franco. 'They kept me very patient.'
The native of Paraguay dropped his second inside a foot for a birdie at the 10th and ran home a 10-footer for a birdie at the par-4 16th.
At the par-5 18th, Franco hit a 2-iron to 15 feet and two-putted for a closing birdie.
'I enjoy playing here,' said Franco. 'I had a couple chances for birdie. My putter was good today.'
Tanaka stumbled out of the gate with a bogey at the first but he responded with birdies on each of his next two holes.
He landed his approach inside 10 feet for an eagle at the par-5 fifth and followed that up with three consecutive birdies to go out in 30.
The 32-year-old from Japan ran home a 20-foot putt for a birdie at the 10th to move to 7 under before cooling off down the stretch. Tanaka dropped a shot with a bogey at the 14th but countered with a birdie at the 15th.
Tanaka faltered again, however, with a bogey at the 16th to share the first-round lead with Franco.
Shigeki Maruyama, David Frost, Kent Jones, Jim McGovern, Brett Quigley and Paul Stankowski shared sixth place at 4-under-par 68.
Luke Donald, who earned his first career victory at this event last year when the tournament was cut to 54 holes due to weather, finished in a group at 3-under-par 69 that featured Presidents Cup player Tim Clark and Corey Pavin.