With partner Reto Götschi, Guido Acklin had a successful career as an international bobsledder for Switzerland beginning in the mid-1990s. His first, and arguably greatest, major international achievement came at the 1994 Winter Olympics, when he finished 0.05 seconds behind his brother Donat and compatriot Gustav Weder to claim silver in the two-man event. Guido and Götschi slid to third place at the 1996 World Championships, but then earned gold in the event the following year. As the reigning world champions they were favored at the 1998 Winter Olympics, but a strong pool of competitors relegated them to sixth place in the two-man. Their record at the European Championships was strong as well: first in 1998 and 1999, second in 1996, and third in 1995 and 1997. They were also the 1997 European Champions in the four-man, with Beat Seitz and the non-Olympian Daniel Giger. Acklin retired from active competition in 1999, but made a comeback two years later, switching his focus to the four-man event. At the 2002 Winter Olympics he came in sixth, alongside Urs Aeberhard, Steve Anderhub, and Christian Reich, and returned to retirement shortly thereafter.