His performances did not go unnoticed and the popular lock picked up not only the Ulster Rugby Personality of the Year award, but also the Ulster Rugby Supporters Club's Player of the Season award.
He also penned a contract extension which will keep him in Belfast until the end of the 2012/13 campaign, as Ulster look to build on their achievement of reaching the Heineken Cup quarter-finals.
Muller is delighted to have been named Ulster captain for the coming season, stating: "It's obviously a great honour for me and I'm really excited and looking forward to a great challenge in 2011/12.
"I think it's going to be a much tougher season, a lot of pressure and a lot responsibility as well and I'm excited about that.
"I enjoy the leadership role. Rory (Best) has done an outstanding job as captain and if I can do as good a job as he has over the past four years then I'll be a very happy man."
He added: "As a captain you only run at the front, there's plenty of leaders in the side, plenty of guys who can make call and captain the side on any given day.
"So for me, it's just about running at the front and making sure the backs make the right calls! I'm really excited and hugely honoured by it."
Ulster, like most teams, will face into the early part of the season without a number of frontline players due to the Rugby World Cup. But Muller believes that after last season's success, the squad need to maintain the momentum.
"It's going to be a much tougher challenge for us this season, partly because of the World Cup but also because last season people didn't really expect us to do well and we surprised them.
"If we want to be a successful side, and a side that can compete in the future with any side in Europe, then we need to be better this year than last year, not just in the quarter-finals and semi-finals but every single week and in every single thing that we do, on and off the field.
"The big challenge not only for me as captain but the whole squad, the management and coaching staff is to make the step up."
Muller, who has spent the past four weeks in camp with the extended South Africa squad while they prepare for the World Cup, returned to Belfast last Thursday.
Originally selected as a replacement for the Springboks' first Tri Nations match against Australia, he withdrew with a hamstring injury but is on the mend.
"Injury wise I'm feeling great, I am starting to run again, it will take a little bit of time to get back to full fitness at my age but I'm feeling great, really fresh and really excited to play again, so I can't wait to get into some of the physical stuff."
Whether or not Muller will be included in the South African squad for the World Cup remains to be seen at this stage.
Having thought that his international career was, in all likelihood, over before he came to Belfast, he is philosophical about whether or not he will get selected but explains that the hunger to wear his national jersey never really goes away.
"It will always be there, if you can play for your country and pull that jersey over your head you will want to do that and it's always a great honour," he admitted.
"If I don't get picked for South Africa again, if I don't get picked for the World Cup that's fine with me. I've got a great challenge ahead over here especially with the captaincy.
"However, if I do get a call-up that would be fantastic, and I would be honoured to go to another World Cup and play another game for my country. Whichever comes my way, I'm a true believer that everything happens for a reason."