For a time after his brother's death he retired from politics, and served in the army in Africa and Sardinia, where he was Quaestor.

His valor, wisdom, and justice made him justly popular, but caused him to be regarded with suspicion at Rome.

In 123 he was elected Tribune, and twice re-elected.
He revived his brother's agrarian law, and became at once the avowed enemy of the Senate.

As a means of increasing his popularity, he endeavored to admit all the Italians to the privileges of Roman citizenship, and to limit the price of bread.
Gains gained the favor of the _Equites_ (Knights), the commercial class, by carrying through the assembly a law by which all judicial functions were taken from the Senate and intrusted to the Knights.

Heretofore all civil and criminal cases of importance had been tried before a jury chosen from the Senate.