Charles E. Lomax, the first black partner at the huge Chicago law firm Sidley Austin, where Barack and Michelle Obama would later meet, died Sunday in Boca Raton. He was 85.

``Charlie Lomax was a terrific lawyer, a trailblazer and a tremendous person,'' Chuck Douglas, chairman of the firm's management committee, said in a statement. ``His enthusiasm for the practice of law and his devotion to his clients was an inspiration for us all. We are saddened by his death.''

After working at Sidley, Mr. Lomax joined the company of one of his biggest clients, the boxing promoter Don King, becoming general counsel and senior advisor to Don King Productions in Deerfield Beach.

``Charlie Lomax was a great friend of mine and a giant of the legal profession,'' King said in a news release.

``He empowered me to fight the system from inside the system. He was a confidant who stood by me for 30 years.''

Born in Wilkesboro, N.C., in 1924, Mr. Lomax served in the infantry in Europe during World War II. He attended college and law school at Howard University.

He spent more than 20 years as a lawyer for the Internal Revenue Service.

In 1975 he became a partner at Sidley Austin, a prestigious Chicago firm that traced its origins to 1866 and represented some of the city's largest companies and institutions.

Barack Obama worked as a summer associate at Sidley, where he met his future wife, a full-time lawyer at the firm.

Mr. Lomax is survived by his wife Corrine of Boca Raton; a daughter, Sharon Elizabeth Elliott; a brother, William Lomax, step-children, David Blaemire, Shelly Blaemire and Gina Collins; and four grandchildren.