He played the role of the young Peter Parker in The Amazing Spider-Man. He also played Max Weaver in the TV series The Neighbors and provided the voice for Sherman in the 2014 feature Mr. Peabody & Sherman.
He grew up in Nashville but was raised in California. In 2010, he appeared in an episode of the HBO television show True Blood.
He appeared in an episode of the TV series Raising Hope.
He has three older siblings. His father is writer and doctor Robert Martensen, and his mother is activist and philanthropist Anne Carver.
He was in The Amazing Spider-Man, which starred Andrew Garfield.