Ciesielski was born in Gdynia, Poland. He received in 1960 his doctorate from the Adam Mickiewicz University in Poznan with dissertation O rozwinięciach ortogonalnych prawie wszystkich funkcji w przestrzeni Wienera (On orthogonal developments of almost all functions in Wiener space) under the supervision of Władysław Orlicz.[3]
He has been a professor at the Mathematical Institute of the Polish Academy of Sciences since 1969 and a member of the Academy since 1973. In 1974 he was an Invited Speaker of the International Congress of Mathematicians in Vancouver.[4][5] He was President of the Polish Mathematical Society from 1981 to 1983.