Former Fleetwood player Coyle has moved for an undisclosed fee on a three-year deal, with the option of a fourth in the club's favour, and will try and help the Tigers out of League One.
The 24-year-old, who was born in Hull and is the younger brother of former IBF lightweight boxing champion Tommy Coyle, has been an established performer at the Cod Army across three loan spells and only joined them permanently in January.
But City's pulling power has seen the former Leeds man move to the KCOM Stadium.
Boss Grant McCann told the club's official website: "Lewie is a fantastic addition to the squad. Although he is only 24 years of age, he comes with a vast amount of experience having played more than 100 games for Fleetwood and was a key player in a side that reached the play-offs last term.
"His attitude, commitment and desire to learn and improve is first-class and – being a Hull lad – he will know what it means to the fans to wear the shirt. Just from speaking to him, the passion he has to do well for his hometown club is clear to see."
Fleetwood boss Joey Barton added: "Hull is Lewie's hometown, so it's a dream move for him and one he couldn't turn down. I spoke to him yesterday about the move and he said he wouldn't have wanted to leave for any other club.
"We are obviously disappointed to lose him, but this was a move which we just couldn't stand in the way of."
The Tigers – previously without a recognised right-back on their books after releasing club captain Eric Lichaj in June and academy product Robbie McKenzie in July – added another new option in the position as Emmanuel joined Coyle in arriving at the club.
The 22-year-old was a free agent after leaving Bolton, having previously played for Ipswich and won promotion from League One during a loan with Rotherham in 2017-18.
McCann said: "Josh has all the physical tools needed to be a modern day full-back. He's tall, strong and is rarely beaten for pace. I'm delighted to have him on board."