Magali Métrailler attended the Istituto Europeo di Design in Milan before becoming interested in watches. When she joined Jaeger-LeCoultre in 2002 at the age of 23 she was the company's first-ever female designer. She quickly made a name for herself inside the company and was given the task to design a rugged new design for the Master Compressor line by Henry-John Belmont. Métrailler chose the classic Polaris Memovox as an inspiration, creating a new case that was more technical and sporting than anything then in the company's range.
Métrailler's first credited design at Jaeger-LeCoultre was the Master Compressor. The case, patented in her name, was based on the new Master Control, with bold yet simple design elements, including a clean bezel, sharply-defined lugs, and flat, un-decorated sides. The dials drew from the classic Polaris Memovox with large trapezoidal luminous markings between upright sans-serif numerals. But the most distinctive feature of the Master Compressor was the notably large locking crowns. The first model to be introduced was the 2007 Master Compressor Géographique with the Master Compressor Chronograph, Master Compressor Diving, and Master Compressor Extreme ranges following quickly after.
The next assignment for Métrailler was the AMVOX, a joint venture with Aston martin. The namesake first model, 2007's AMVOX1 draws strongly on the Polaris Memovox, the clearest link to that model until the Tribute to Polaris that followed in 2008. Métrailler was also credited with the AMVOX2 Chronograph, AMVOX5 World Chronograph, and Master Compressor Extreme LAB. She was also credited with the design of the Gyrotourbillon 1, having been involved with the project since her start at the company.
After 2012, Métrailler began doing freelance work for other companies. She is associated with the modern Ball brand, and is credited with their Ball For BMW line including the Ball For BMW TimeTrekker. She also designed the Ball Engineer Master II Pilot GMT, Ball Engineer Master II Slide Chronograph, and Ball Engineer Master II Diver Worldtime.
Métrailler is specifically credited with the following watch designs:
- 2004 Jaeger-LeCoultre Gyrotourbillon 1
- 2004 Jaeger-LeCoultre AMVOX family
- 2007 Jaeger-LeCoultre Master Compressor family
- 2008 Jaeger-LeCoultre Polaris Memovox
- 2012 Ball For BMW TimeTrekker
- 2014 Ball Engineer Master II Pilot GMT
- 2014 Ball Engineer Master II Diver Worldtime
- 2015 Ball Engineer Master II Slide Chronograph
Some sources spell her last name as "Metrayer".