Richards has 27 Bathurst starts to his name, equal fourth on the all-time list, with victories in 1998, ’99, ’13, ’15 and ’18.
The son of seven-time Bathurst winner Jim, Steven also competed in 14 full Supercars Championship seasons for a best of fifth in 2004, with a total of 10 championship race wins from 460 starts.
"I’ve been in discussion with Charlie and the team regarding an active role for some time,” said Richards, who finished sixth in this year’s Great Race alongside Winterbottom.
“It's an exciting time at Team 18 and now is the right time to make this decision.
“I’ll be able to utilise my experience to assist Charlie and the team drive success both on and off the track and work closely with the incredible team partnerships that have been established.”
Richards declared it the end of his Supercars driving career, but isn’t ruling out racing in other championships, having spent recent years between Carrera Cup and Australian GT.
Richards' full-time career started at GRM
His time in Supercars included stints at the likes of Garry Rogers Motorsport, Stone Brothers Racing, Gibson Motorsport, Perkins Engineering, Ford Performance Racing and Triple Eight.
“I’ve had a fantastic career in Supercars, winning races, competing for championships, and driving with the best teams and drivers in the most competitive touring car championship in the world,” he said.
“While I close the door on Supercars I’ll still have some flexibility to continue driving in other categories.”
Schwerkolt said a non-driving role within the team for Richards had been floated when he first joined at the start of the year.
"Really sad day for us to announce Richo is hanging up the helmet on his Supercars career, but his move into the management and commercial side of Team 18 will be great future proofing for the team,” he said.
“We have been chatting about this for a while when Richo first joined the team at the start of the year, but now with the expansion to a two-car operation, the role has really progressed into a full time role.
“Richo has extensive motorsport knowledge and is a massive get for our team to have someone of his calibre that can guide and assist all Team 18 properties. Really really proud to have him on board!"
Team 18 has not announced co-drivers for either of its cars for the 2020 PIRTEK Enduro Cup, as a busy market continues to unfold.