West Memphis Three
At the time of their arrests, Jessie Misskelley, Jr. was 17 years old, Jason Baldwin was 16 years old, and Damien Echols was 18 years old.
Ricky Jackson, Ronnie Bridgeman, and Wiley Bridgeman
Ricky Jackson (born 1957), Ronnie Bridgeman (born 1957) and Wiley Bridgeman (born 1954) are African Americans who were wrongfully convicted of murder as young men in Cleveland, Ohio in 1975 and sentenced to death. Their sentences were commuted to life imprisonment in 1977. They were imprisoned for decades before each of the three was exonerated in late 2014. Jackson and Wiley Bridgeman were released that year. (Ronnie Bridgeman, by then known as Kwame Abuja, had been paroled in 2003 after 28 years in prison, and had been successful in his new life.) 
According to the National Registry of Exonerations, Jackson was imprisoned for 39 years on this wrongful conviction. This is believed to be the longest record for someone who has been exonerated. Wiley Bridgeman served nearly as long.