The Football Association of Wales have confirmed Rowberry will remain in his role as Craig Bellamy's assistant with the Wales national team.
And Walters added: "Welcoming two assistant managers of such calibre and with such innovative and progressive mindsets in Paul and James is another important part of how we will seek to progress and grow."
Robins led the Sky Blues to promotions from League Two and League One and reached the Championship play-off final in 2023 before losing to Luton on penalties.
They failed to match that top-six finish last season but did take Manchester United, where Robins started his playing career, to a penalty shootout in the FA Cup semi-finals.
He has also had spells in charge of Rotherham, Barnsley, Scunthorpe and Huddersfield.
Stoke started the season under Steven Schumacher but sacked him in August to appoint former Huddersfield and Norwich coach Pelach.
However, they won just three of his 19 games in charge and the 36-year-old was sacked on 27 December after a 2-0 home reverse by Leeds stretched their winless run to nine matches and left them 18th in the Championship.
Robins is now the club's seventh managerial appointment since their 10-year spell in the Premier League came to an end in May 2018.
They are yet to finish in the top six of the Championship since being relegated.
"With the proven track record Mark brings to the role, I believe this is a genuinely exciting moment for Stoke City," said Stoke chair John Coates.
"The recent win over Sunderland, with the way the team competed on the field and connected with the fans, gave everyone a huge boost and provided a glimpse of what can be created at our club."