Porterfield, 36, will combine his playing career with a job as consultant fielding coach, working with the men's and women's teams and the Ireland pathway system. He has also be named as Wilson's assistant at the North West Warriors in Ireland's interprovincial set-up.
Recognised as one of Ireland's best fielders, Porterfield's last international appearance came in an ODI in January 2020, having stepped down from the captaincy a few months earlier.
"I'm really excited about these two roles - both working within the national system and within the provincial system in the North West," Porterfield said. "I had a bit of a taste of coaching with the Birmingham Bears last year, and am looking forward to working with some of Ireland's most talented players - being able to pass on knowledge and experience from a coach's perspective. It will be a bit different being a coach while still playing, but it's going to be a great opportunity and I can't wait to get stuck in.
"The fielding role with Ireland is something I'm passionate about. I've prided myself on my fielding throughout my career, and tried to set high standards, so hopefully I'll be able to help not only players from the senior men's and women's squads, but players from the under-age teams as well."
Having called time on his professional career to take over as North West Warriors head coach and pathway manager, Wilson has also been given a consultant wicketkeeping role with Ireland, again working across men's, women's and age-group teams.
Wilson said: "I'm thrilled to be able to support keepers up and down the Irish pathway in this new role. It's a great opportunity to get back involved in the international set-up so soon after retirement, and it's a role I'm looking forward to massively.
"When I was initially discussing the scope of the role, what I really felt added to it was the ability to share my knowledge and experience with the keepers within the women's game. Ed [Joyce] has been doing such a fantastic job as head coach, and I'm delighted to be able to work with him on bringing on the senior and emerging talent that we have here in Ireland."
Richard Holdsworth, Cricket Ireland's high performance director, added: "I'm delighted that we have not only appointed these two roles we have long sought, but to have appointed two world-class players like William and Gary represents a real win for Irish cricket and the players in our performance system.
"For any young player to be able to access and learn from two of the best players Ireland has produced is an immense opportunity. I know both William and Gary have a passion for Irish cricket and are keen to help develop and improve Irish cricketers at all levels. I wish them well, but know they need no additional motivation - they are two of the most self-motivated people I have worked with and I look forward to seeing their work in this new capacity."