The goalkeeper - who spent the last few seasons playing at Hampton before retiring last year - replaces Mel Gwinnett who left the club earlier this month.
The Beavers finished ninth in the Vanarama National League South this season after winning just once in their final nine league games.
Julian won the FA Trophy as a player with Stevenage and also counts promotions with Bromley, Newport, Gillingham and Billericay on his CV.
Speaking directly to the Beveree faithful following his appointment, he's desperate to bring similar success to his current side.
He said: "I've had the privilege to be involved in some unbelievable successes in my career which I never take for granted and I understand the level of hard work it takes to achieve that success.
"I'm determined to make sure this club and these fans get to create more memories and continue to win. I can't wait to get started and to see everyone at the Bev."
He added: "This club has meant a lot to me for the few years that I've been here. It is a club with family and community at its core and that has always resonated with me.
"Speaking to [Managing Director Will King] Will and the board, I am really excited about the project here at Hampton & Richmond. I'm a big believer that clubs and squads should operate as sustainably as possible, whilst always driving to be the very best and trying to win every single game."