[1][4] With long-time climbing partner Kurt Albert, he revolutionized the training techniques for sport climbers, and the introduction of the campus board in particular.

[9] Güllich made several notable trips to the US,[5] coming to international attention in 1982 with the first repeat of Tony Yaniro's historic 1979 8a (5.13b) route, Grand Illusion in Lake Tahoe.

[9] On a 1986 trip, Güllich made his iconic free solo of Separate Reality, 7a (5.11d), in Yosemite, photographed by Heinz Zak [de].

[9] On a 1986 trip to Britain, he did the world's first-ever free solo at 7c (5.12d) on Weed Killer at Raven Tor,[11] but broke his back falling on Master's Edge at Millstone.

[12] In 1984, Güllich would begin an extraordinary series of years where he would create several hardest new grade sport climbs in the world – the most of any climber in history.

[1][2][5] In 2019, Francis Sanzaro, the editor of Rock & Ice, called the 1991 photograph of Güllich, mid-flight on the crux dyno of Action Directe, as "the most iconic photo of hard climbing ever taken".

[1][14] In 1991, with Kurt Albert, Bernd Arnold, Norbert Bätz and Peter Dittrich, they made another breakthrough in big wall climbing with Riders on the Storm (IX A3) on the Paine Towers in Patagonia.

[9] After moving to the Frankenjura in 1981, Güllich spent eleven years sharing an apartment, which included a gym in the cellar, with his life-long climbing partner Kurt Albert.

[18] On 29 August 1992 Güllich fell asleep at the wheel of his car and veered off the autobahn between Munich and Nuremberg as he made his way home from an interview.

[1] In 2022, Die Zeit called Güllich, "One of the best unknown athletes that have ever existed in Germany", noting that rock climbing was still a developing sport in the country.