Gildart was born in Hindley, Greater Manchester, England to Claire[3] and Ian, a former professional rugby league footballer for Wigan, Wakefield, and Oldham.

[5] A product of Wigan's junior system, Gildart made his Super League début on loan for Salford Red Devils in 2015, making a total of three appearances before returning to his parent club.

He then kept his place in the Wigan team for the remainder of the 2015 season, including an appearance in the 2015 Super League Grand Final at Old Trafford in only his tenth career match.

One of the signature tries of the year was scored by him in an away match in Perpignan as he straightened up the line and seared his way to the try-line after a flowing length-of-the-field attack by Wigan.

Gildart scored a try in the 2016 Super League Grand Final against the Warrington Wolves which brought Wigan level at 6–6 before they went on to win 12–6 at Old Trafford.

[citation needed] Gildart played in the 2018 Super League Grand Final victory over the Warrington Wolves at Old Trafford.

[14] In round 10 of the 2021 Super League season, Gildart scored two tries for Wigan in a 18–8 defeat against Hull Kingston Rovers.

On 1 August, Gildart signed with English side Leigh Leopards until the end of the 2023 Super League season.