Altom ("Al" and "Tom" combined - the names of his grandfathers) represents individuals, businesses, and tribal nations across the United States. In 1999 he founded the law firm that eventually became mctlaw. With offices in Washington, DC; Seattle, Washington; and Sarasota, Florida; the attorneys and other professionals of mctlaw represent clients in a broad range of litigation and business and tribal development.

Altom has practiced extensively before the Court of Federal Claims and been very involved in promoting the mission of the Court. He served as the 2016 President of the Court of Federal Claims Bar Association. In 2019, Altom was awarded with the Court of Federal Claims' Golden Eagle Award for his work on behalf of the Court.