During the ICC Annual Conference in Kuala Lumpur, Isaad was inaugurated as the eighth president of ICC. The 60-year-old Isaac is a former chairman of New Zealand Cricket (NZC). He will hold office for a two-year term.
Speaking after taking charge, Isaac said: "When I look at the list of previous Presidents, I am reminded of the importance of this office."
He continued: "In the midst of my pride at being chosen as President, I recognise that there is, of course, much hard work and much progress needed if we are to maintain the game's current healthy state. I believe that the challenges ahead are no less daunting than those we have faced in the last two years if we are to maintain the vibrancy and viability of the three formats of the sport.
"We are fortunate as a sport - indeed unique - to have three different formats at international level. We will all strive not only to preserve those formats but to build on their foundations. In that way the ICC will continue to oversee a great sport and we will all work to make it even greater."
He said that he was looking forward to serve the game with "honesty and integrity."
"I look forward to serving the game with honesty and integrity and to the best of my ability. I look forward to handing on the guardianship of the sport with the game enjoying even greater health."
The ICC also got a new Chief Executive as former South Africa wicketkeeper Dave Richardson took charge from Haroon Lorgat, who served for four years.
Also on Thursday, the ICC said that it had decided to create the post of ICC Chairman, remove the role of Vice-President and vary the role and powers of ICC president.
Richardson, who played 42 Tests for South Africa and has been ICC's General Manager, Cricket for the last 10 years.
Richardson said: "It is a real honour to be confirmed as the ICC Chief Executive and I want to pay tribute to Haroon Lorgat. I have learnt much in the last four years and I inherit a game in great health with much to be optimistic about. I look forward to building on that and tackling the challenges ahead."