Keane, 31, has a base salary this year of $2,917,741 according to figures released on Friday by the MLS Players Union.
His total compensation is $3,416,243, which includes a pro-rated portion of his signing bonus and other guaranteed compensation.
Galaxy teammate David Beckham, the former England captain, is the highest paid player in the league with $6.5 million in guaranteed compensation.
He's followed by New York Red Bulls teammates Thierry Henry of France ($5.6 million) and Rafa Marquez of Mexico—a former Barcelona defender ($4.6 million).
Galaxy's Landon Donovan, at $2.3 million is fifth, the only home-grown US player in the top five.
All of those five are considered "designated players"—whose compensation can exceed usual salary cap limits.
Seven-figure salaries are uncommon in MLS, with nine players making more than $1 million this year.