Loss was born in 1958 in Winterthur, Switzerland. He studied Medicine at the University of Zurich for two years before transferring to physics. 1985 he obtained his PhD in physics in Zurich with a thesis on statistical mechanics under the supervision of A. Thellung. After postdoctoral stays in Zurich and at the University of Illinois in Urbana, where he worked with Anthony Leggett, he worked as a research scientist at the IBM T. J. Watson Research Center in Yorktown Heights. In 1993 he became professor at the Simon Fraser University in Vancouver, Canada and since 1996 he is full professor at the University of Basel.