Prior to co-founding CalebAndonian, Joseph honed his litigation skills at the Public Defender Service for the District of Columbia - often recognized as the leading training ground for trial attorneys in the United States - where he served as lead counsel on over fifty trials against local and federal prosecutors.  Joseph then built a highly successful solo practice, which focused on criminal and civil matters in D.C. and Maryland in state and federal court.  Joseph's civil-litigation work includes representing plaintiffs who have suffered catastrophic personal injury and civil rights violations.

In 2018, Joseph was selected by The National Trial Lawyers as a "Top 40 Under 40" lawyer - a distinction extended exclusively to trial lawyers doing civil plaintiff and criminal defense work.  The National Trial Lawyers again recognized Joseph's accomplishments in 2020, this time naming him a Top 10 trial lawyer nationwide in his areas of expertise.  

Joseph has served as an adjunct mock-trial instructor in the past and as well as a guest lecturer on a variety of legal topics.

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In July 2021, a panel consisting of D.C. Mayor Muriel Bowser and the Chief Judges of the D.C. District Court, the D.C. Court of Appeals, and the D.C. Superior Court appointed Joseph to serve on the Board of Trustees for the D.C. Public Defender Service.