There are not many decent numbers to choose from when joining the Boston Celtics due to all the retired ones. Jrue's #21 is retired for Bill Sharman, while Payton Pritchard wears #11, which Holiday wore in New Orleans and Philadelphia. Of course Pritchard chose #11 since his #3 from college was retired for Dennis Johnson.
According to Holiday he settled on #4 due to his siblings and former Celtics point guard Isaiah Thomas.
Jrue Holiday said he chose No. 4 because of he and his three siblings (4) and because of @isaiahthomas.