Turnbull is well regarded among fans, having played up front in the mid nineties - but extending his affiliation with the club by scouting and running the extensive operations of the SUFC Trust (formerly the club's Football In The Community scheme).
He was delighted to follow in the footsteps of Cliff Byrne, Alex Calvo-Garcia and Steve Cammack in throwing his support behind the Iron Trust.
It was an easy decision for the former striker to make, as he spends a lot of time working with community groups in the area and sees a lot of shared values.
"As a Community Trust I fully understand the values of working with our local community. The Iron Trust will hopefully provide both a sounding board and voice for all Iron fans," he said.
"By listening to the views of supporters we can all pull together for the benefit of the Football Club, both on and off the pitch."
It caps a great few weeks for the Iron Trust, which included representing members at the club's AGM of shareholders for the first time.
The Iron Trust are also working with the football club to produce a document releasing information about this year's accounts.
"Lee's support is a huge fillip for everyone connected with the Iron Trust," said John Needham, secretary of the Iron Trust's interim board.
"Part of the Iron Trust's aim is to help the club's community relationship, something that is mirrored in Lee's role with the SUFC Trust seeking to use football to help our communities.
"The Iron Trust has come a long way in a short space of time, and the interim board feels we are making real progress with the club."
The Iron Trust had 224 members as of Monday December 17, with membership costing £10 for adults, £20 for families (2x adults + unlimited U16s) and £3 for U16s. Scunthorpe United fans can join on matchdays, or via their website.