Husain Mijali, who announced his decision on Sunday, said he would not stand as a candidate in forthcoming elections for the Bar Association Council.
Mijali said the move was a protest against a proposed new law for union elections.
The voting mechanism in the new law, to be presented to parliament on Wednesday, will prevent any block from gaining a majority in the Association Council, he said.
This "violates the constitution and law" and is "tantamount to banning professional unions in the kingdom", he added.
Jordan has regularly been censured for interfering in trade union affairs.
In a recent statement, the International Confederation of Free Trade Unions condemned Jordan for attempting to prevent freedom of association and for meddling in union elections.
However, the Jordanian government has previously said that unions were violating the law by engaging in politics.
According to law, associations must confine themselves to internal and professional issues.
"The government respects people's right to freely express their opinion within the boundaries of laws that regulate such freedoms ... [but] nobody is above the law"
Officials said unions engaged in illegal political activities such as rallies, sit-ins and demonstrations and the displaying of political banners.
Government spokeswoman Asma Khadir previously told the Jordan Times: "The government respects people's right to freely express their opinion within the boundaries of laws that regulate such freedoms."
But she added: "Nobody is above the law."