Grant grew up in the estate auction business, Mroczek Brothers Auctioneers, owned by his father Lawrence C. Mroczek. Grant, along with his brother Michael Mroczek, are third-generation auctioneers in this family business. He has spent 20-plus years organizing, cataloguing, and conducting estate, art & antique, and specialty collectible auctions. He is also an avid collector of 20th century Northwest and American art, sports memorabilia, historical medals, American studio pottery, and much more.
Mroczek Brothers Auctioneers, located in Renton, Washington, has conducted more than 1,700 estate auctions in its 45-year history. They currently conduct 25-plus estate auctions bi-weekly at their auction gallery, selling an average of 500-plus antiques, collectibles, art, jewelry, coins, etc. They also conduct 6-plus art and antique auctions a year specializing in Northwest, American and European original art, antique silver and porcelain, and a variety of rare and unusual items. They have also conducted specialty auctions for collections of coins, militaria, lunch boxes, trains, etc. In addition to auctions held in their auction gallery, they conduct over 12 on-site auctions a year, specializing in the complete estate liquidation of personal and real property.
Through the auction house and private sales, Grant has assisted thousands of collectors in the acquisition and evaluation of items. He has also volunteered as an auctioneer at numerous charity auctions, helping raise money for many local organizations.