CalMac managing director Martin Dorchester is to step down in March, the ferry operator announced today.
The move follows the Scottish Government-owned firm winning a new £900 million, eight-year contract to run its west-coast network, which started last Saturday.
Mr Dorchester has been with the UK's largest ferry operator for four years.
The process to find his successor will start shortly.
He said: “It has been a huge privilege to work at such an iconic Scottish company.
"When I joined the company my primary task was to win the next Clyde and Hebrides Ferry Services contract, and with that now done, I believe it is the right time to step down and seek a new challenge."
David McGibbon, chairman of parent company David MacBrayne, said: “Under Martin’s leadership we have successfully won the new contract to run Clyde and Hebrides ferry services and, in addition, he led the team which secured the contract to run the Marchwood Military Port in Southampton.
"He leaves the group in a great place to win the next Northern Isles contract [which private sector operator Serco won in 2012 until 2018] and to retain the Gourock-Dunoon ferry service contract."