He will oversee the WRU national age grade coaching programmes and play a key role in designing the relevant coaching structures and systems that underpin the player pathway from age 16 through to senior level.
As part of his new role he will also liaise with the national and regional squad coaches to integrate performance programmes across the performance systems of Welsh Rugby. Lewis has worked at regional and national level in Wales and has a wide range of experience coaching in England.
He has been a head coach at Newport, formerly coached with Celtic Warriors and was an assistant coach at Llanelli, as well as coaching at Moseley and Bridgend. He was an assistant coach to Wales' first full-time professional Head Coach Kevin Bowring and took charge of the senior squad backs and was a selector under Bowring's successor Graham Henry between 1998 and 2001.
His previous experience also includes coaching the Wales U15, U19 and U21 teams which led to his appointment as National Senior A team coach.
WRU Group Head of Rugby Joe Lydon, said: "We are delighted to have secured the services of a coach of Allan's calibre and experience. He has strong opinions on how the pathway structure should progress and his arrival will herald a new phase of development on top of the good work already achieved at both regional and national age grade.
"Allan has the rare blend of vast experience coupled with great enthusiasm and understanding of the modern game. More importantly he has the skills and experience in coaching and developing both players and coaches in order to fulfil individual and collective potential.
"Allan is the first of a series of new appointments we are set to announce in the coming weeks and I am eagerly looking forward to working with Allan and the prospect of enhancing our systems and processes to ensure we continue to builds a coherent, strong and positive Welsh rugby culture."
Lewis will join the WRU from his current position as the Director of Coaching at Hartpury College in Gloucestershire.
He said: "These are exciting times for Welsh rugby and I am very much looking forward to playing my part in sustaining the future of our national game. Without the structures below, no senior side can ensure sustained success and it is only through getting things right at the National Academy level that senior rugby can thrive.
"We will be taking an holistic approach to coaching across the age grade levels and working closely with the coaches at senior level to ensure consistency of messages and to exchange ideas, but, most importantly, to ensure that we are producing the right kind of rugby players to excel at elite level when their time comes."