Steve Caldwell joined Newcastle in 1997 as a product of their Acadamy, and is the older of the Caldwell brothers at St James' Park. Caldwell played for Newcastle Acadamy and the Newcastle Reserves before finally breaking in to side in 2000-01 against Manchester City in September 2000. Caldwell is a strong and powerful centre half and went on to play 10 more times that season for Toon.

Caldwell scored his first and only goal in a black and white shirt when he lashed home the winner in the 4-3 Worthington Cup win against Bradford City at St James' Park in November 2000. On the international scene, Caldwell made his Scottish Under 21 debut against France at Kilmarnock in March 2000, and a little more than a year later, in April, Steve made his full Scotland debut in Poland when he came on in the second half to help his country to a 1-1 draw in an international friendly.

Caldwell fell down the pecking order at the club and went on loan for a month to Blackpool in the early part of the 2001/02 season, and then went for two months at Bradford City in December 2001 to January 2002. However, Steve impressed in the first team when he played against Middlesbrough in November after injuries to key players and scored in the game, and went on to play another 16 times for the Magpies that season.

Caldwell rejected a new deal at the club in May 2003, but signed a new one year contract the following month as the Scottish defender looks to consolidate a place in the team next season.