Augustin, whose one-year deal was first reported last week, adds another defensive player to the cupboard for head coach Dwane Casey.
The 25-year-old, who was selected ninth overall at the 2008 NBA draft by the Charlotte Bobcats, spent last year with the Indiana Pacers.
"He was one of the young, experienced point guards we thought could come and bring something to our program," Ujiri said after Augustin met the media for the first time at Air Canada Centre. "I like the experience. He's been a starting point guard in the NBA. (He) struggled at times a little bit last year. Good outside shooter for the most part and he can run a team."
In 358 career games with Indiana and Charlotte, Augustin has averaged 9.6 points and 4.0 assists in 24.5 minutes. The New Orleans native's numbers were down in 2012-13 (4.7 points, 2.2 assists, 16.1 minutes in 76 games) while coming off the bench for the Pacers, who made it to the Eastern Conference final.
"Winning solves a lot of problems. With the Pacers we won a lot games so the atmosphere was a lot better and guys worked hard," Augustin said. "We took it serious. In Charlotte it was a little different, with losing you get down.
"Hopefully here we can get going on the right track and guys can have that winning atmosphere."
Augustin, who is expected to back up starting point guard Kyle Lowry with the Raptors, sees potential in Toronto.
"There's a group of young guys who are pretty good and have a chance to be very good — hard workers," he said. "That's the type of person I am and I want to come in and work hard with those guys and try and change things here in Toronto and make it to the playoffs."
Augustin plays in the summer against Lowry and expects there to be chemistry with his new teammate.
"(Lowry) is a tough guard," he said. "He's going to help me on defence, just being tough and being vocal out there and I think we can help each other a lot."
The University of Texas product joins former Pacers teammate Tyler Hansbrough, who signed a two-year deal with the Raptors earlier this month.
Ujiri has had a busy off-season since taking over basketball duties from the departed Bryan Colangelo. His biggest move came when he traded under-performing centre Andrea Bargnani to the New York Knicks for Steve Novak, Marcus Camby, swingman Quentin Richardson and a couple of draft picks.
The club also recently signed guard Dwight Buycks, averaged a team-best 18.0 points a game last season for Gravelines in the French Pro A league in 2012-13.
Augustin, meanwhile, says he has learned a lot in his five seasons in the NBA.
"It's a business. The NBA is a business but you've got to represent yourself well," he said. "It's a job and you've got to take every day seriously and go practise hard and play hard and things will work out."