The pair rescued the County's first innings on the opening day of in their LV= Insurance Championship Division Two clash against Gloucestershire at Bristol on Monday.
Rossington’s unbeaten 66 was key on a grey, cool day at Bristol with the visitors recovering from 147 for five to make 232 for five at the close having lost the toss.
It was the Northants captain's fourth half century of the summer.
But Gouldstone's innings was also an eye-catcher as he made 32 not out from 90 deliveries, hitting four boundaries.
“There was definitely a bit in it and the lads up top played well to blunt the new ball," said Rossington, who saw his team slide from 67 without lost to 147 for five.
“Gloucestershire then started to bowl better and got their rewards but then we had a good finish to the day with that partnership.
“It’s the first time I’ve batted with Harry but he was brilliant out there and played some lovely shots."
Rossington has grown as a batsman since being handed the Championship captaincy midway through the 2019 season and here was the latest of his captain’s innings.
He drove Matt Taylor through cover and Tom Price past his left boot for early boundaries. Ben Charlesworth was pulled wide of long leg and Graeme van Buuren worked fine for four more, just after reaching a half-century in 58 deliveries.
Further boundaries followed in what proved to be the day’s last action.
He drove and edged Taylor between slip and gully and then, looking to whip to leg, saw a leading edge fall just short of the cordon. Perhaps the misjudgements gave the umpires encouragement to take the players off.
Gouldstone was also very easy on the eye.
A 20-year-old born in Kettering, he made his first-class debut in this fixture, abandoned after just one session due to Covid, a year ago.
He appeared to have plenty of time as he punched Price off the back foot past point, worked Charlesworth through square leg and drove him through cover to raise the 50 partnership - perhaps the day’s best shot.
With fixtures in Division Two and Three taking on the same context as juvenile contests at the same stage of the flat racing season - prep for next summer and the chance to collect some prize money - performances like Gouldstone’s are essential to keep September relevant.
In that regard, Gloucestershire had 21-year-old Price playing his fourth first-class match. He took the first two wickets - the prize scalp of Ricardo Vasconcelos, who edged a ball of tight line low to second slip for 37, and Luke Procter, who sent a skier back to the bowler trying to pull.
Taylor also took two. Emilio Gay’s pleasant 44 ended lbw when he was struck in line but above the knee roll. Rob Keogh then shouldered arms but edged into his middle stump.