The 18-year-old this afternoon penned a new four-year deal having recently returned from the First Team's pre-season training camps in Spain and Austria.
His decision to commit his future to the Club follows those made by Luke Shaw, Lloyd Isgrove, Jordan Turnbull, Jack Stephens and James Ward-Prowse, all of whom have signed new contracts during the past 12 months.
Chambers has started all of Saints' senior friendly matches so far, putting in accomplished performances at right-back against formidable opponents in games against FC Schalke 04 and Beşiktaş.
He has now been rewarded with a new extended contract ahead of Southampton's new Barclays Premier League campaign, which gets underway in 17 days' time.
Chambers has already made his senior debut for the Club, appearing as a substitute in a Capital One Cup win at Stevenage last August having been involved heavily during pre-season ahead of the 2012/13 campaign.
The England Under-19 international will now hope to follow in the footsteps of his former Academy teammates Shaw and Ward-Prowse, who established themselves in the First Team last season.
"It's fantastic – it's like my dream, really," said a delighted Chambers after putting pen to paper.
"I've been at the Club since I was so young, so this is a great feeling. I've been here since I was seven and I've been treated really well so it means the world.
"The Club has a great set-up and it's going through a really good time at the moment. There are going to be big things from Southampton in the future.
"I've always wanted to play for the First Team at this club, and this is another step towards that," he continued.
"I'd like to push myself into the First Team and to prove myself there. I went out [to Spain and Austria] to prove a point because I feel I'm ready, and hopefully I have done that.
"There is a pathway from the Academy for everyone, and hopefully I'm showing that now so I really want to step on."
First Team Manager Mauricio Pochettino was present as Chambers finalised his new contract, and commented: "I'm delighted to see another young player commit their future to the Club.
"Calum has shown in his performances in pre-season that he is more than capable of performing at this level, and we hope that this commitment allows him to push on and thrive within the First Team environment.
"He settled into the group nicely during our training camp, demonstrating his maturity off the pitch as well as his quality and potential on it while playing against a good standard of opposition.
"From the beginning of my time at Southampton, Nicola [Cortese, Executive Chairman] spoke to me of his project of bringing young talented players through the Academy and into the First Team, and that was something that really appealed to me.
"To now see Calum – along with many others – make that step up pays great testament to the hard work that goes on here that is driven from the very top."
Calum Chambers with Mauricio Pochettino this afternoon
In Profile – Calum Chambers
Chambers has been with Southampton since the age of seven, progressing through the Club's youth sides before agreeing a professional contract in April 2011.
He has featured in midfield as well as in defence for the Under-18s and Under-21s over the past two seasons, but has now signalled his intention to focus on his progression as a right-back.
Chambers made 23 appearances for the Under-21s last season, scoring four goals including a vital late equaliser at Manchester United in the first half of the campaign.
He has represented England at Under-17 and Under-19 level, helping the Under-17s win the Algarve Tournament in February 2012 by scoring against France and Holland.
Calum also netted in a UEFA European U17 Championship Elite Qualifying Round win over Ukraine the following month before stepping up to the Under-19 squad later that year.
He now has nine Under-19 caps under his belt, and continued his good goalscoring record by netting in the Young Lions' wins over the Faroe Islands and Turkey during the 2012/13 season.
Calum joined the First Team for their pre-season trip to the French resort of Évian-les-Bains ahead of the 2012/13 campaign having been promoted into the First Team along with Ward-Prowse, Shaw and Stephens.
He made his senior debut in August of last year, coming on as an 84th-minute replacement for Dean Hammond in a Capital One Cup second-round win at Stevenage.
He was also an unused substitute for a third-round game at Leeds United, and returned to the bench for the final Barclays Premier League match of the season at home to Stoke City in May.
Chambers was one of four Development Squad players called into the First Team for this month's pre-season trips to Spain and Austria, travelling overseas for 18 days.
He started all four friendlies played during that time, featuring in wins over Spanish sides UE Llagostera and Palamós CF as well as high-profile matches against German giants FC Schalke 04 and Turkish club Beşiktaş.
With a new long-term contract now signed, Calum will look to continue his bright start to the season by challenging Nathaniel Clyne for the right-back slot in the coming campaign.
Chambers in action against Schalke last Wednesday