Morrison declined to comment further and would not be drawn on his next career move, but Craigs Investment Partners analyst Mark Lister said it was good timing.
"People are always disappointed to lose a CEO that's well liked by the market and by investors but at the same time Nigel has done his time," Lister said. "He's been there for a while and he's presided over a lot of changes and developments for the company, most notably making some progress on the convention centre and those issues, new licences in Auckland and Adelaide and redoing Federal St.
"He will be able to step down feeling like he has made a real difference."
Chairman of SkyCity Chris Moller said the board had been discussing a succession plan with Morrison since September, agreeing it was the right time for a new chief executive.
It has appointed chief operating officer John Mortensen as interim chief executive, pending a global search for the new leader.
Over his tenure as chief executive, Morrison has netted around $21 million in salary and bonuses and since he was appointed to the role the company's share price has risen from $4 to just over $5 last month. Forsyth Barr analyst Jeremy Simpson said this had been a tough period.
"In the last 10 to 15 years there have been some challenges and the regulatory environment has got a bit tougher," Simpson said. "[That was] impacted by smoking bans going back about 10 years, and there's really been no real growth in gaming spend generally in New Zealand and on a per capita basis it's gone backwards over the last 10 to 12 years, so that environment makes it a bit tough."
Simpson said building up other revenue streams, in particular the development of the Federal St area to attract visitors, had been important for the business. And the convention centre deal including the increased carparking was vital for the long-term growth of the company.
Casino revenue has been boosted by high tourism and migration numbers, helped by the business purchasing its second Queenstown casino in 2013, as well as a corruption clampdown in Macau resulting in New Zealand and Australian casinos becoming more common destinations for big-spending customers.
The share price has risen 28 per cent in the past 12 months but closed down 3.8 per cent to $4.76.
Nigel Morrison
• Stepping down April 29
• Been in the role for 8 years
• Earned roughly $21 million as CEO
• Former CFO of Hong Kong and Macau casino group Galaxy Entertainment
• Has more than 30 years of gaming industry experience