Müller grew up in the small town of Aarau, west of Zurich. He began skiing at an early age. He would skateboard in the summer which prompted him to move away from skiing and try out snowboarding - as he felt snowboarding was better suited to complement his skateboarding. Müller spent a lot of time at the nearby winter resort of Laax.
2005 brought Müller to the attention of the mainstream as he was voted Transworld snowboarder of the year. Since then he has appeared in numerous snowboard videos and has placed in some of the largest snowboard competitions of the world - having placed first in the TTR O'Neill Evolution Quarter Pipe and the TTR 4 star Popcorn Snickers Classic Wallride, in 2007.
Despite these wins, Müller does not focus his time on competitions as do many other professional riders. He is better known for his appearances in countless snowboard videos - showcasing his style and ability.
Müller is a vegetarian and pursues a sustainable lifestyle. In collaboration with Burton's Green Mountain Project, Müller has been raising environmental awareness amongst snowboarders. The Green Mountain Project product line focuses on utilizing recyclable material and eco friendly solutions to create a product that has minimal impact on the planet.
Part of the Green Mountain Project is the EcoNico snowboard, named after Müller, which has a FSC farmed woodcore and various recycled materials.
In an effort to reconcile his usage of helicopters and snowmobiles, he offsets his carbon footprint by donating to the SuddenRush Atlantic Rainforest Institution.