Having made 130 for Yorkshire against Middlesex and 104 not out in last month's first Test against Sri Lanka, the left-hander added 110 as England reached 219 for six in reply to India's 295 in the second Investec Test.
"It's a great place to play cricket and it's gone well this season," Ballance said. "It was quite a tough pitch this morning but once you got in, it was a good day to score runs.
"We lost a few wickets early on and to be fair they bowled well, but [Ian Bell] and I tried to hang in and scrap, thinking 'hopefully the runs will come later on' and they did.
"It's still a good pitch and if we can keep them in the field a bit longer we can get a good lead."
The 24-year-old made the wrong sort of headlines on the eve of this match when pictures emerged of him swaying and stripped to the waist in a Nottingham nightclub after the first-Test stalemate.
On the pitch, there were few indiscretions from a batsman who makes a particular virtue of patience. It took Ballance 54 balls, either side of lunch, to reach double-figures. But his confidence to wait for bowler error, and punish it - always leaving and defending well in between - helped him pass 50 for the fourth time in only eight Test innings to date.
He eventually made it two centuries in three attempts at Lord's, following his unbeaten 104 against Sri Lanka last month, characteristically cashing in with a sudden rush of five boundaries in nine balls as India's fourth seamer Stuart Binny filled in overs with the old ball.
He had one let-off on 32 when he edged a delivery which left him down the notorious Lord's slope, the ball flying between wicketkeeper Mahendra Singh Dhoni and Shikhar Dhawan at first slip for four. "Looking at it again, I probably could have left it," he admitted. "When you look round, it feels great to see it going through there. Once you get in, you feel like you're batting on a flat pitch, but early on you do have to think about it."
His century, though, was somewhat overshadowed by another failure from captain Alasdair Cook. The captain's wretched run of form has become an inescapable issue, and it will remain so until either Cook rediscovers the prolific runscoring knack which has conspicuously eluded him for 26 Test innings, or his twin responsibilities as opener and leader are relaxed. A critical point is surely close, but at least Ballance ensured England still have a feasible opportunity to break their run of nine Tests without a victory.
That was in major doubt when - after Cook and opening partner Sam Robson had been dismissed for the addition of nine runs by Bhuvneshwar Kumar (four for 46) - England faltered first to 31 for two and then 113 for four.
Cook and Robson have yet to register a half-century stand, in six attempts together, after the England captain followed some movement across him and edged behind to a diving Mahendra Singh Dhoni to become the first of Kumar's victims.
And he soon had his second wicket, Robson aiming a drive only to also edge behind. The nagging seamer struck again soon after lunch with a short ball which followed Ian Bell down the slope and had him gloving a simple catch to third slip.
Joe Root was a determined ally to Ballance until he went unluckily lbw to Ravindra Jadeja, having apparently got an inside-edge on to his pad in forward-defence.
Moeen lent more lasting support until he missed a flick to leg to give part-time off-spinner Murali Vijay his maiden Test wicket. When Kumar then returned with the second new ball to have Ballance caught-behind down the leg-side, it was India who again edged the honours.