Law has penned a two-year contract at Valley Parade after finalising his move back to the Bantams this Wednesday. The deal is subject to international clearance due to Law's previous time in Scotland.
Subject to the deal also being ratified by The FA and EFL, Law will officially become a Bradford City player on Friday (1 July 2016) when his contract with Glasgow Rangers expires.
A return to City for Law will see him feature in the club's claret and amber colours for a third time in his career after two previous loan spells in 2007 and 2008, both when McCall was manager.
The 28 year-old, who is comfortable playing wide or in a more central position, has also played for McCall in Scotland at Motherwell and Rangers.
Law was part of the squad at Ibrox last season that helped return Rangers back up into the Scottish Premiership.
The midfielder played 54 times for the Gers the previous season as well - the 2014/2015 campaign - netting an impressive thirteen times in the process.
During his time north of the border, Law also played European football in the UEFA Champions League and Europa League competitions for Motherwell.
After making his original Bantams debut back in 2007, Law is probably best remembered by City supporters for his part in the club's 2008/09 campaign.
The busy midfielder, only 20 years-old at the time, played a sizeable role in the Bantams' season, featuring in 35 games from October onwards as City narrowly missed out on the League 2 Play-Offs.
Speaking about his return to Valley Parade, Law said: "I am delighted to be coming back to Bradford, and it is a bonus that it will be with Stuart again.
"I thoroughly enjoyed both loan spells here before, particularly the second one. With Stuart and Kenny (Black) here as well, they are the two people who I've probably had my best seasons with.
"The club has improved a lot since I last came here and looks to be on the up. Speaking to the manager and listening to his targets for the season ahead, it seems exciting times and a fantastic club to return to."
McCall added: "I know Nicky inside out both as a player and as a person. I've managed to get the best out of him in the past and that's what I'll be aiming to do again.
"I want him to get back to what he's good at, and that's getting forward from the middle of the park or a wide area and scoring and creating goals.
"He's at a good age. He's coming up to his prime and he is hungry for more success after a good spell in Scotland.
"He's desperate to do well here."
Born in Plymouth, Law made his professional debut for Sheffield United in October 2005 in an EFL Cup tie at Reading.
In the following 2006/07 season, Law actually featured in four Premier League fixtures for the Blades, before enjoying a loan spell with Yeovil Town towards the end of the campaign.
While at Sheffield United, Law met up with McCall for the first time, with the City legend acting as the Blades' assistant manager at the time.
After his two loan spells with the Bantams, Law left Bramall Lane for Rotherham United in 2009.
He helped Rotherham to the League 2 Play-Off Final in his very first season - the Millers eventually losing out to Dagenham & Redbridge at Wembley Stadium.
With Law continuing to impress in the red and white of Rotherham, he eventually earned a move to Motherwell, and reunion with McCall, in July 2011.