GL Seaman & Company | 2,858 followers on LinkedIn. Extraordinary at work; MillerKnoll Certified Dealer | GL Seaman & Company, a MillerKnoll Certified Dealer, is a greater Dallas-Fort Worth leader in contract furniture and interior construction solutions. Our partners include Knoll, Herman Miller, DIRTT Environmental Solutions, and more than 200 additional manufacturers. As one of the largest full-service dealers in the Southwestern United States, we manage numerous global, national, and regional projects for some of the nation’s best-known companies.