He is one of the PRAJAPATIS created by BRAHMA to help with building the Universe. He is also another of the Seven Seers (the SAPTARISHIS) with an advanced understanding of the entire cosmos. Luckily he is keen to share his wisdom with humankind.
He also owns the sacred cow NANDINI, who was given to him by INDRA. This is very beneficial for him — she has magic powers and can grant any wish. The only problem is that people are always turning up asking to borrow her.
One particularly persistent pest was VISHVAMITRA, who just wouldn’t take no for an answer. Luckily VASHISHTHA has infinite patience and fortitude. If you possess a magic cow, those are the first things you should wish for.