Source: BFFC
Jason Wingreen was the original voice of Boba Fett. We just learned he passed away on December 25, 2015. This is our tribute to him.
https://www.youtube.com/watch?v=I4UYzn0KGM0
Anyone who saw The Empire Strikes Back in theaters or on VHS/laserdisc between 1980 and 2003 would have heard his lines. After 2004, DVD and Blu-ray releases were re-dubbed to conform to the prequels and used Temuera Morrison as Boba Fett.
Jason was born October 9, 1920. He was interviewed for Star Wars Insider #49 (May/June 2000) in which he shared this story of the role:
My agent called me and said to go over to the recording studio, where I met Gary Kurtz and Irvin Kershner. Normally, you see the face of an actor you're dubbing, so you have to lip-synch. But that was no problem here -- I could say the lines at any time. I got in position, they ran the film a few times, and I said the lines. Kershner came out and made a suggestion or two and went back in the control room, I did it again, and I was finished.