He has been replaced by former Citrix US senior director of corporate consulting and education, Karl Liebman, who assumed the position last week. O'Brien will remain at Citrix in an advisory capacity until June 30.
O'Brien insisted he had not fallen out with Citrix management and said Liebman's relocation to Australia had been planned for some time.
"I want to slow down. I've been in the IT industry for 30 years and it's time to get off the hurdy-gurdy a bit," he said. "I still want to keep my finger in from a consulting point of view and perhaps serve on company boards. But I'll look into that when I finish at Citrix. This is my chance to spend time with my family, go golfing and do all those things."
In a statement, area vice-president for Asia-Pacific, Dennis Rose, thanked O'Brien for his commitment to Citrix. He pointed out the company had experienced 12 per cent year-on-year growth last year, which was above industry standard.
O'Brien said now was a good time to leave, as the company had chalked up an excellent Q1 and was looking at strong Q2 revenue.
"It's good to go out on a high - we've been producing some good results in A/NZ," he said.
O'Brien joined Citrix six years ago as marketing director for Asia-Pacific, and assumed the area vice-president role two and a half years ago. Prior to that, he spent 23 years with IBM.
He said he was now talking to several parties about opportunities. While keen to remain in IT, he would consider any options that involved building a team.
"If the right opportunity comes up, and it suits me from a timing point of view, I will go down that route," he said.