He has been coaching at Huddersfield Giants this year but returns to Hull College Craven Park where he last operated in 2016.
“I am ecstatic to be back here at Hull Kingston Rovers,” said Poching, who replaces James Webster.
“Whilst my last tenure did not quite finish the way that we wanted it to (relegation), I have many fantastic memories and I also get to work with many great people again.
“I hope it is a seamless transition even though the playing group has changed, “I have worked with Tony (Smith), for a long time, and (assistant) Dave Hodgson before too.
“There is a lot of work ahead but I’m excited to get started.
“Tony coached me towards the back end of my career at Leeds and we tasted success there.
“After my playing career ended, he gave me the chance to go into coaching. “Moving to Warrington, and ever since then, pretty much everything I have learned about the game has come from him. I know what he expects of me and the group.”
Poching, who first arrived in the UK as a ball-playing back-row for Wakefield Trinity in 1999, said: “I understand the area of east Hull.
“And I got to learn about what this club means to those people in the stands and this community.
“I grew to love my time here before and I know what everyone expects of us as a team.
“I want those supporters to be proud of this side, to give them something to shout about and for us to be successful.
“The fans live for coming here every single week to watch the team and they want maximum effort. Hopefully we, as a team, can give them that success in 2020.”
Smith added: “Willie knows the fabric of the place and loved his time here. He is very passionate about it and he is aware of the style of coach that I am and the style of play we desire here.
“He is very capable and a very competent coach that can deliver the right kind of training to help our players improve.
“The last time that Willie was here he was given a role of ‘defence coach’. Willie or Hodge (David Hodgson) will not have any sort of tag this year. The three of us will coach all relevant aspects of the game. If the team performs well in attack and defence, the credit is shared.
“If we do not succeed in any aspect, the buck stops with me.”