Deakin replaces Gary Hayward, who left the club after just over a month in charge following Saturday's 3-0 defeat at Mickleover in FA Cup first round qualifying.
On the league front, the club have won just three of their opening six matches following their lateral move into the Northern Premier League ahead of the 2023/24 season.
Deakin will be joined at the Robins by a coaching team of Craig Swinscoe, Adam Campbell and Ben Hutchinson.
Deakin and Swinscoe will be no strangers to the Robins supporters, having both played and coached previously at the New Manor Ground.
The pair were part of the coaching team that took the club to back-to-back promotions in the 2017/18 and 2018/19 campaigns.
Former Middlesbrough and Celtic striker Hutchinson and Mansfield Town academy graduate Campbell join Deakin’s setup as first team coaches.
“It’s good to be back," Deakin said following his appointment.
"I’ve got very fond memories here, and hopefully we can get the place rocking again.
"As a team, we are really looking forward to getting started and bringing good times back to the football club.”
Photo credit: Ilkeston Town