Channel Five chief executive Dawn Airey and the station's programme boss are to leave following media magnate Richard Desmond's takeover.
The channel will also shed between 60 and 80 jobs from its 300-strong workforce.
Ms Airey, director of programmes Richard Woolfe and managing director Mark White are among a number of senior executives who will leave in the coming months, staff were told.
Mr Desmond's company Northern & Shell - which also owns newspaper Daily Express and OK! magazine has also announced plans for £1.5bn of investment in the channel over the next five years.
This is said to involve "a focus of resources on programme and content development".
Ms Airey will remain for several months and is leaving to take up a senior role at the RTL Group, Five's former owner.
Yesterday's announcements are the first major moves since Mr Desmond's purchase of the channel last month from RTL in a £103.5m deal.
Ms Airey will continue in her role for the time being "to facilitate the implementation of a cost-efficiency programme" which aims to return the firm to profitability.
She said: "The day Five was sold, my job was done. I will be returning to the RTL Group but over the next few months will remain in post with a number of my senior colleagues to facilitate the integration of Five into Northern & Shell."