Salmon was the son of Nahshon and grandson of Amminadab. Aaron was Salmon's uncle, by marriage to his Aunt Elisheba. He was a member of Tribe of Judah and was in the line of Perez. His father, Nahshon was the Chieftain of the Tribe of Judah.
He was the father of Boaz, by the prostitute Rahab. It is unlikely that Boaz was the result of prostitution between Rahab and Salmon.It is recorded that at the time of the Israelite Battle of Jericho that Rahab had a family including a father, mother, brothers and sisters, but no husband is mentioned. Prior to this battle, Jericho was Canaanite territory and an Israelite would not have met Rahab. Furthermore Rahab lived in Israel after Jericho is conquered and she is called righteouss. Based on all of this Salmon likely married Rahab rather than having Boaz out of wedlock.
Despite his fatherhood to Boaz, Salmon nor Rahab are mentioned anywhere in the account of Boaz; other than the genealogy (only Salmon).