However, Gloucester hit back and Freddie Burns dropped a neat goal to nudge his side in front 23-24 with just four minutes to go.
Bur, when composure was needed, Gloucester transgressed at a ruck and Lamb earned his side the win.
It was harsh on the Cherry and Whites for whom Brown, Buxton and James were willing ball carriers and tacklers and Jonny May and Charlie Sharples constant threats in attack.
But there was much to impress from both sides and a promise for a long season ahead.
Both teams were forced into making late changes. Northampton drafted in Andy Long at hooker in place of Brett Sharman while Matt Cox came in for Gloucester in the back row instead of Brett Deacon.
The pre match drizzle had ceased and everything was set fair at Franklin's Gardens for a cracking game of rugby although the skies overhead were murky and the floodlights switched on before kick off.
Gloucester showed ambition from the off, running back a loose clearance from Myler, and were rewarded with an early penalty attempt as a Saints tackler failed to roll away from the tackle area but Tim Taylor was off target with his first shot at goal.
An entertaining phase of play followed with Sharples and May attacking from deep for Gloucester but the Saints defence was good and Myler settled things down with a good touchfinder.
The Saints were also looking to attack and turned down a 13th minute kick at goal in favour of kicking to the corner. Gloucester held comfortably but conceded a more kickable attempt which Myler drilled through the posts to open the scoring.
The Gloucester pack responded well, forcing a penalty on a Saints scrum put in then carrying the ball on powerfully. New Saints lock Samu Manoa went off his feet to concede another penalty and Tim Taylor made it 3-3 after 19 minutes.
However, Gloucester didn't clear sufficiently well from the restart and found themselves under immediate pressure. A neat inside break and offload from Stephen Myler found Phil Dowson who showed great strength to make the line and Myler converted for 10-3.
However, similar immediate generosity from the home side saw Jonny May charge down Greig Tonks' attempted clearance and May stayed on his feet to control the ball, win the race and score. Taylor converted to draw Gloucester level. It was the best possible response.
Gloucester were asking questions and May was almost away again as he hacked on a loose ball but was just halted by a despairing last ditch tackle.
Gloucester's pack regrouped and forced a penalty on a Saints scrum and Taylor slotted it for a 13-10 lead on the half hour.
Backed by a suitably partisan home crowd, Northampton were right back in Gloucester's faces. A quick tap almost caught Bryan Redpath's side napping and only scrambling defence kept the line intact.
However, a free kick conceded at a 5m scrum gave Saints scrum half Martin Roberts a chance to tap and go and the summer signing just made the line near the posts, the try given after consultation with the TMO. Myler added the extras for a 17-13 lead.
There was a chance to respond as the home time allowed a Taylor up and under to bounce and Gloucester poured through but Dave Lewis was adjudged to have knocked on just as Tim Taylor was setting himself for a drop goal.
That was it for an entertaining first half with Gloucester possibly aggrieved to be behind after a fairly even opening 40 minutes.
Gloucester had enjoyed plenty of possession but the home team had taken their chances when presented with them. All to play for after the break.
No changes at half time but Gloucester were dealt a blow after 43 minutes when Alex Brown, who had run the lineout superbly, had to leave the field to be replaced by Tom Savage who duly made his first team debut.
It was then first blood to the home side as their pack forced a penalty after a prolonged phase of possession and Myler landed the penalty to open up a 20-13 lead.
And the task got even tougher when Peter Buxton was yellow carded on 50 minutes for what appeared to be hands in the ruck and Myler compounded the misery by adding the three points on offer.
Now with a ten point lead in hand, Northampton knew that they just had to play smart and keep Gloucester at bay and a more pragmatic approach was duly adopted.
An opportunity was missed for Gloucester when Freddie Burns was just off target with a 56th minute penalty although he made amends on the hour for a 23-16 scoreline.
The game entered its final quarter and a note of tension crept into Franklin's Gardens despite the still vocal home support as Saints strove to put the game to bed whereas Gloucester knew they were still within just a score.
And Gloucester struck on 71 minutes. Lesley Vainikolo made the half break, Jonny May took it on and looped a pass for Charlie Sharples to sprint home and score. Burns was wide right with the conversion that would have levelled the scores.
Ryan Lamb was just short with a penalty which would have eased Northampton nerves and Freddie Burns duly dropped a goal to give Gloucester a 76th 23-24 minute lead and hint at a smash and grab win.
However, Lamb showed great character to step up and slot a penalty as Gloucester came in at the side of a ruck to sink his home town club and earn instant hero status with his new club.
Gloucester had one last chance but couldn't make anything of a lineout in the home 22 and had to settle for a losing bonus point.
|Northampton Saints Score Card|
|Gloucester Rugby Score Card|