The S4C Unitary Board has appointed Sioned Wiliam as interim Chief Executive.
Sioned is well known in the industry as a former BBC Radio 4 Comedy Commissioner and former Head of Comedy at ITV.
She was previously a programme producer at Talkback and Hat Trick.
She will start her work with the Welsh-language broadcaster part-time in March, before joining S4C full-time in April.
Her appointment comes following the sacking of previous Chief Executive, Sian Doyle in November, after a report said she bullied staff.
Sioned's main responsibility over the coming months will be to lead on S4C's Action Plan, which has been approved by the Unitary Board, and follows the publication of the Capital Law Report.
The plan sets out a programme of work to fully address the issues S4C has faced since 2022.
The aim is to restore the trust of S4C staff and the creative sector by looking at the leadership, culture, HR policies and procedures, and governance of the organisation.
As part of the plan external experts will lead a review of the organisation's values, there will be an external review of the effectiveness of S4C governance, managers will receive training on leadership and change management, and internal communications will also be strengthened.
Following the appointment of Sioned Wiliam, Geraint Evans will continue in his role as interim Chief Content Officer and Elin Morris will continue as S4C's Chief Operating Officer.
It is also expected that the Secretary of State for Culture, Media and Sport will appoint an interim Chair soon to lead S4C's Unitary Board.
Rhodri Williams, Chair of S4C’s Unitary Board, said: “I look forward to welcoming Sioned to S4C following an unprecedentedly difficult time for our workforce.
“Sioned's leadership experience as well as her background and experience in the industry brings a breath of fresh air to S4C, and her priority will be to ensure the Action Plan inspires change across the organisation – for the benefit of our people, the creative sector and of course our audiences.
“I know Sioned is keen to get to grips with restoring confidence and trust in S4C, ensuring that S4C is once again a happy place to work, that people feel they can be at their best and do their best for S4C and the Welsh language.
"On behalf of the Board’s Non-Executive Directors I would like to thank S4C's staff and Management Team for their dedication and professionalism over the past few months, knowing that they will give Sioned every support to implement the Action Plan and restore faith in S4C."
Sioned Wiliam S4C's interim Chief Executive said: “I'm incredibly grateful for this opportunity to be part of the story of S4C - a channel that has been an integral part of my life since it began - as a viewer, producer, presenter and as a grateful mum.
"S4C's offering is very special and the relationship between the channel and the audience is vital – I look forward to doing everything I can to facilitate this.
"I want to make sure S4C is a good place to work, where staff are respected and supported. Everyone involved with the channel must be able to trust it knowing it will work for the benefit of the workforce, stakeholders and audience."