Born in Matupá, in the central state of Mato Grosso, he took up athletics at a young age, initially focusing on the high jump.

He moved to Porto Alegre and had his first success at the 2010 South American Youth Championships in Athletics, where he took the gold medal.

[6] He backed this up with a performance at the top level Madrid Indoor Meeting in February, winning with a world-leading mark of 17.35 m (56 ft 11 in) ahead of former world and Olympic champion Nelson Évora.

He improved further to 17.41 m (57 ft 1+1⁄4 in), two centimetres short of the new leader Will Claye, and left with a silver medal from his senior global debut.

[8] After 2018, Almir dos Santos had a series of injuries, and only in 2022 he returned to compete at a high level, reaching the final of the triple jump at the 2022 World Athletics Championships, finishing in 7th place.