Conversation so far:
When did Walter Cronkite start Walter Cronkite's career?
1935.
what was his job?
a series of newspaper reporting jobs covering news and sports.
what newspaper did he write for?
CANNOTANSWER.
when was he first on air?
he joined the United Press in 1937.

Question: What was his first big story?
Self-contained rewrite: What was Walter Cronkite's first big story?