Glamorgan started the day on 41-2 and were almost strokeless for the opening stages as Ul Hassan and departing captain Sam Northeast saw off the initial spells from Tom Bailey and Balderson.
Northeast looked settled for his 21 when Jack Blatherwick had him given lbw in the 20th over of the day, prompting a standing ovation from the Sophia Gardens crowd as tribute was paid to the Kent-bound batter over the public address for his successful four years with the county.
Ul Hassan started to get his off-drives away and seemed set for a hard-earned 50, but fell for 45 as he reverse-swept Tom Hartley to a diving Keaton Jennings at point.
Glamorgan moved ahead with four wickets down but with more balls keeping low, Balderson then got Lancashire dreaming of a day off with a double strike.
He appeared to be appealing for leg-before against Kiran Carlson on eight, but the ball lobbed to Jennings at slip and umpire Tom Lungley decided it was inside edge onto pad.
Billy Root, who has been offered a new contract, guided his first ball from Balderson for four but was leg-before two balls later, meaning four wickets had fallen for 34 either side of lunch.
The ultra-experienced pair of Colin Ingram and Chris Cooke halted the slide with a stand of 50, but Tom Aspinwall had Ingram lbw for 37 with one that skidded through and Timm van der Gugten slapped the same bowler to point.
Balderson’s fourth wicket came with the second delivery of the new ball as Mason Crane was lbw for a brisk 23, including five fours.
Cooke hoisted Balderson over mid-wicket for six to bring up his 50 but holed out off Bailey, leaving Lancashire to score at 5.1 per over if they wanted an extra day off.
Luke Wells (19) started expansively before driving van der Gugten to mid-off, but Jennings launched him over mid-on for six before taking 19 off a Harris over.
His runs came off just 33 balls and included three sixes before he chipped Crane to mid-wicket, while Josh Bohannon hammered a quick 33 in poor light.
Northeast sent down the final over to mark his departure as Lancashire won the match but Glamorgan took the season’s honours.
Glamorgan captain Sam Northeast told Sport Wales:
“I had a lovely reception all day, it’s been a bit emotional and the applause was a fantastic way to walk off the field. I’m sure no-one wanted to see me bowl but even bowling, there was nice applause.
“It’s not the way I wanted to end, but we got the result of getting promoted and it’s been hard work for a few years trying to achieve that and the preparation starts in November. The fact this result didn’t go our way doesn’t take anything away from what we’ve achieved.
“It’s a tight division and we played exceptional cricket through the middle period, everyone’s played their part and the next challenge is to stay up.
“it feels like I’ve played my whole career here weirdly, the last four years have been very enjoyable and I’ve felt at home here so it’s going to be strange going back home (to Kent) and seeing the boys in Div One. To go back to where I started will be a nice way to finish my career, though it hasn’t sunk it yet.”
Lancashire captain Josh Bohannon told Lancashire Sport:
“(On captaincy) Pretty cool isn’t it? I’ve been vice-captain for a couple of years and at some stage there’s going to be a time when you get the arm-band.
“It’s nice to have your own spin on it, nice working with all the coaches and with Jimmy (Anderson) over the last couple of months, we think about the game on the same wavelength and I’ve learned a lot from him.
“It’s not gone our way (this season) and we’ve not achieved what we wanted, to be promoted, so it’s frustrating. We didn’t play good cricket for the first half of the season.
“But from when Crofty (interim coach Steven Croft) took over, apart from the Glamorgan game at Old Trafford, we were in a position to win every game. It’s really positive we’ve managed to turn it round in such a short period of time.
“Jimmy’s led from the front, and it feels like we’re getting back to being Lancashire again.”