Fajdek's early promise was evident when he won gold at the 2013 World Championships in Moscow. At just 24 years and 69 days old, he became the youngest male athlete to achieve this feat. He continued to dominate the sport, winning gold at four consecutive world championships from 2013 to 2019.

| Season | Event | Rank |
|---|---|---|
| 2021 | Men's Hammer Throw | B Bronze |
| 2016 | Men's Hammer Throw | 17 |
Throughout his career, Fajdek faced several injuries. In 2011, he sustained a partially torn thigh muscle and knee problems. The following years saw him dealing with a strained ankle, a cut finger, and torn calf muscles. Despite these setbacks, he made remarkable comebacks each time.
After the 2016 Rio Olympics, Fajdek returned to coach Jolanta Kumor. However, in October 2020, he switched to training under Szymon Ziolkowski, an Olympic gold medallist. He also moved from Agros Zamość to AZS AWF Katowice in August 2020.
Fajdek resides in Żarów with his partner Sandra Cichocka and their daughter Laila, born in 2015. He holds a degree in Physical Education from the Academy of Sport Education in Warsaw. Fluent in English and Polish, he enjoys playing video games during his leisure time.
Fajdek's accolades include the Golden Spike award in 2013 and 2015, the Gold Cross of Merit in Poland in 2015, and being named Athlete of the Year in Zamość (2015) and Sportsman of the Year by the Polish Olympic Committee (2013).
In early 2019, while recovering from a calf injury, Fajdek changed his diet and lost 16 kilograms within a year. In 2021, he co-founded the sports clothing label Forever Stronger with fellow Polish athletes after being dropped by their sponsors.
Looking ahead, Fajdek aims to win a medal at the rescheduled Tokyo Olympics. His previous attempts at the Olympics in 2012 and 2016 did not yield medals, but he remains determined to succeed this time.
Fajdek's journey is marked by resilience and dedication. His achievements serve as an inspiration to aspiring athletes worldwide.Fajdek's early promise was evident when he won gold at the 2013 World Championships in Moscow. At just 24 years and 69 days old, he became the youngest male athlete to achieve this feat. He continued to dominate the sport, winning gold at four consecutive world championships from 2013 to 2019.