Movie

Morgan Freeman first movie appearance was in an uncredited role, when he was 27 in Sidney Lumet's The Pawnbroker. His first major role though in Brubaker, came in 1980, when he was 43. And that is the reason why he often ended up playing the supporting lead or the wise old man sort of characters.
Amitabh Bachan was 27 when he made his debut in Saat Hindustani(1969), however a series of flops meant he had to face a long period of struggle. He was already 29 when he began to get noticed with movies like Anand, Bombay To Goa, Parwana. However when his breakthrough sucess Zanzeer came in 1973, he was 31 then, though you would not guess seeing this image.
And then followed Deewar, Sholay, Muqaddar Ka Sikandar, Trishul, Don all of which made him the uncrowned king of Bollywood then. His best phase sure came after he turned 30.
Shammi Kapoor made his debut in 1953, with Jeevan Jyothi, when he was 22. However a series of flops, and forgettable movies, meant his career was not going anywhere. However Nasir Hussain's Tumsa Nahin Dekha and Dil Dekhe Dekho were hits and gave a fillip to his career. The movie that however defined his "Yahoo, Rockstar" image, Junglee was released in 1961, when he was 30, and that really made him one of the top stars. Post Junglee, Shammi Kapoor rocked the youth, with a series of hit musicals, his aggressive form of wooing, his energetic movements, all hit a chord with the youth, and all this when he was in his 30's. Interestingly both Amitabh Bachan's Angry Young Man image and Shammi Kapoor's Yahoo image became quite established when these actors were in their 30s, and they actually looked younger than their age.
Another actor who became famous in his 30's, was none other than our Bihari Babu, Shatrughan Sinha. While he had made his debut in 1969 with Sajan when he was 23, for a long time, he was playing mostly villian or side hero roles. He was 31, when Kalicharan was released in 1976, and that movie made him one of the top most heroes. Kalicharan put him in the top bracket, made him one of the big stars of the 70s, and there was no looking back.