Gary Kirsten's tenure in charge of South Africa will end on July 31 after he decided not to renew his contract for a further two years. Kirsten, who was appointed in 2011, cited the needs of his sons, Joshua and James and daughter, Joanna, who are all under the age of 10, as the only reason for him opting not to continue to be in charge of the team he took to No.1 on the Test rankings. His last assignment will be the Champions Trophy in England before he settles in to spend more time with his family.

"I feel I can no longer cope with the lengthy periods of separation from my family that this job demands," Kirsten admitted. "Last year, I had 250 days away from Cape Town, my home. I believe my absentia as a father is compromising my responsibilities to my family. I've just had five weeks at home now, which is the longest period I have had there for a few years and I began to realise the impact my absence as a father has had on my family."

When Kirsten took the job as South Africa coach, he made it plain to his employers, CSA, that his first priority was to his family. His contract included terms relating to the amount of time he could spend at home, even during the season and on tours, because he did not want the job to rob him of his primary role of husband and father.

At the time, he and his wife, Deborah had a policy in place about the maximum number of days they would spend apart - 21. Kirsten also assured her if the separation ever became "unbearable", he would not continue as coach. He has now decided it has reached those levels and Deborah was among the most surprised by that conclusion.

"I don't think she believed me when I said I was not going to renew," Kirsten said. "But that's how I feel about the importance of the institution of family. I don't want to be a statistic so that when my kids are grown up, they say they didn't see their dad. Right from the outset of my contract, it was a concern - how I would be able to manage the time apart. I even considered doing only one format of the game but we felt it would be unfair on many people. The last five weeks at home have made me more aware of my responsibilities."

Kirsten denied that political reasons pushed him, although there was some suspicion he was under pressure for a slow transformation rate, especially in Test cricket. Although South Africa has not had a quota system in place for several years, it was widely frowned upon that no black African played in the longest format for South Africa during Kirsten's time in charge. "No, that has nothing to do with it. I've given my reasons and those are 100%," he said.

Kirsten leaves South African cricket in a healthy state at Test level, where he had the best record of all past coaches. The team won 63% of the Tests they played and Kirsten was the only coach who took them to No. 1 in the world with victory over England. "The Test team moved to new heights," he said. "We've got an incredibly strong senior player base. They are the heartbeat of the team and they drive the values and the culture of the team, so I move away very comfortable that that is in place."

His limited-overs returns were not as striking. So far, Kirsten is the third-worst performing coach in the fifty-over game with a win percentage of only 56%. He conceded, "performances in ODIs and Twenty20s haven't been where we wanted them to be. But we've built a good base of players."

After winning the World Cup with India in 2011, Kirsten was widely thought to be the man who would help South Africa finally lift that trophy. But he said that was never part of his plans. "It was not my intention to go to the World Cup. My work is part of a process to help the players and South African cricket reach the goals they want to reach," he said, although he did have some advice for the man who takes South Africa to the 2015 event. "Going into the World Cup in two years, we don't have to shift the team around too much."

Kirsten has one more chance to achieve success in the fifty-over format with the team in a month's time. He pledged to approach the Champions Trophy with "renewed vigour," but after that family will have him around almost full-time.

Kirsten confirmed he will not seek any other employment immediately although he will not rule out contributing to South Africa in a consultancy role. "I like to think my time is not done. I don't think I will ever leave coaching but it would have to be in a way that suits my needs," he said.

CSA will appoint a committee to handle the appointment of the new coach, who will take over for the limited-overs series in Sri Lanka in July and August. Kirsten himself could be involved in the process and hinted his assistant, Russell Domingo may be best placed to take over.

"My relationship with Russell has always been a close one. He is passionate and clinical and he has done a lot of coaching. I have no doubt that he is very capable of doing high-level coaching jobs," he said. Domingo and bowling coach Allan Donald's contracts also expire at the end of July and they will only know if they will continue in their roles after the new head coach has been appointed.

Donald appears interested in continuing. He is currently coaching Pune Warriors in the IPL and told ESPNcricinfo that if it was up to him, he would stay on. "I spoke to Gary personally a couple of days ago and I respect his decision 100%," he said. "At the moment we are very focused on the Champions Trophy and I'm sure that this team needs no motivation to go and win this tournament for Gary. As far as I'm concerned, we've just got to let this whole thing take its course and, for me, there is no decision to be made about my future with the Proteas."

Firdose Moonda is ESPNcricinfo's South Africa correspondent