His brother was the one actually auditioning for the role of Short Round in Indiana Jones and the Temple of Doom (1984). Jonathan just followed his brother along, but the casting people decided to pick him instead.
Attended Alhambra High School in Alhambra, California, USA.
In the scene in The Goonies (1985), where rocks are falling from the cave ceiling, he screams "Holy S-H-I-T", spelling the expletive rather than saying it. He did this because his mother made him promise not to use any bad language in the movie.