After graduating from the Academy of Fine Arts in Łódź in 1966, he worked as a design specialist in a fabric factory in Białystok. Between 1975 and the Martial Law of 1981 he was working as artistic director of the Kontrasty monthly. Since then he devoted himself entirely to art. In 1990 he was also one of the co-founders of Tygodnik Białostocki, a Białystok-based local weekly. He authored the graphical and artistic finish of hundreds of books of various Polish publishing houses.
Since 1983 Gajl became interested in heraldry. For two of his books detailing the coats of arms of the Polish-Lithuanian Commonwealth he prepared more than 4000 illustrations. Because his illustrative work is often used over the internet and many foreign publications, the style of the illustrations he prepared is often referred to as herb gajlowski, or Gajlesque Coat of Arms. He is also the author of modern emblems adopted by, among others, the city of Białystok and Podlaskie Voivodship.
- Ornatowski.com: http://www.ornatowski.com/index/herbyszlacheckie_g.htm
- Wyszukiwarka herbów szlachty polskiej: http://gajl.wielcy.pl/