First of all, the player’s agent will earn a percentage of the player’s gross income with the club.
Furthermore, the agent also often gets a percentage of the transfer fee that is being paid in order to transfer the player. This means that if the player is being transferred for X million €, the agent gets a percentage of this X million €.
In principle, the commissions are paid by the clubs, and not by the player. However, be careful with clauses in the representation contract which provide that the player should pay the agents. In such cases the football agent could also claim commissions directly from the player.
Next to that some football agents also often earn a percentage over the commercial contracts (sponsorship contracts, image rights contracts, boot deals,…) the players sign. In such cases the agent fee will be deducted from the money the players are receiving out of the commercial deals.
The above mentioned earnings explain the official business model of football agents but all too often they also have kickbacks or commissions for any insurance, investment property, financial products,…their clients purchase through their mediation. These kind of earnings are most of the time not disclosed to the football players.