The 21-year-old midfielder will agree a new six-month agreement with the Buddies that will tie him to the Scottish Premiership side until January 1.
Newton racked up 20 appearances for Danny Lennon's men during a similar stint north of the border last term.
He ensured his name will live in Saints folklore forever with a goal in the 3-2 triumph over Hearts at Hampden that secured the Scottish Communities League Cup.
And he claims he knocked back moves to the SkyBet Championship to link up with his old side once more.
Newton told Press Association Sport: "I had offers from a few clubs in the Championship but I decided to come back to St Mirren, partly because they couldn't guarantee me football.
"At this stage in my career I really need to be playing games, so I think St Mirren are the right club to come back to.
"From the gaffer Danny to his assistant Tommy Craig and the other backroom staff and the lads, they are a great bunch. I really missed that dressing room when I went back to Newcastle in the summer.
"St Mirren gave me my first shot at football and that meant a lot to me, so coming back is best for both parties."
Newton arrived in Paisley at the turn of the year and linked up with Newcastle colleague Paul Dummett.
The left-back seems to have now cemented a place in Alan Pardew's first-team squad after he was recalled to Tyneside.
Now Newton hopes to pair up with another of his young Newcastle associates, with St Mirren closing in on Campbell.
Lennon faces competition for the England Under-19 striker, with St Johnstone also interested.
However, Newton is ready to do his bit to confirm the 18-year-old's capture, saying: "I've already had a word with Adam and told him what the club is like.
"I told him it would definitely be a good move for him to come up here and play. If the deal is done for him to come to Saints I'll be the first one to welcome him. He can definitely benefit up here."