Zac Ward has signed a three-year contract with UIster which will keep the winger at the club until 2028.
The 26-year-old joined Ulster on a trial after impressing for the Ireland Sevens side at the Paris Olympics in the summer.
Ward, whose father Andy won a European Cup with UIster in 1999, made his debut for the province in last week’s Champions Cup defeat by Bordeaux.
“After the summer Olympics in Paris, I was ready for a change after some amazing experiences with the Ireland Sevens programme,” said Ward, who has retained his starting spot for Friday’s United Rugby Championship game with Munster.
“I always dreamed of playing for my home province as a boy, as I watched my dad play in an Ulster jersey growing up.
“I’m also mates with a few of the guys who were already in the side and the others were fantastic in welcoming me into the set-up.
“With the help of the coaches, players and staff here, I want to kick on and hopefully make plenty of good memories playing for Ulster.”
Ulster general manager Bryn Cunningham said: “We identified Zac as somebody who could be a good addition to the Senior squad, and we have been impressed with how he has settled into the group.
“Watching his performances in the Sevens game, we felt that he showcased a number of transferable skills for the XVs game, with his strengths in ball-carrying, his speed, aerial skills, and try-scoring ability all strong attributes for playing in the backfield.
“It’s also a great example of someone who hasn’t come through the traditional route into the senior men’s side, so credit to Zac and the journey he has been on.”