Hornbuckle oversaw MGM International’s purchase of Mandalay Resort Group and helped consolidate the corporate structure of MGM during the Great Recession. He helped expand MGM International from owning just 1.5 properties in Las Vegas to owning 30 properties around the world, including 19 regional resorts. He received the Hospitality College's 2019 Industry Leader of the Year Award. As CEO, he helped successfully guide MGM Resorts through the 2020 pandemic, when resorts across the world shut down to avoid spreading the disease.
Hornbuckle started his Las Vegas career working as a busboy and room service attendant at the Jockey Club and later became an assistant hotel manager at the Flamingo Hilton. He worked for 15 years at Wynn Resorts, opening the Mirage with Steve Wynn in 1989. He became President of Caesars Palace in 1997 and joined MGM Resorts International in 1998. During the great recession, Hornbuckle became MGM Resorts’ Chief Marketing Officer, and in 2012 he was appointed President of MGM Resorts International. He became COO in 2019 and was chosen as the Acting CEO at the beginning of the COVID-19 pandemic in March 2020. In July of the same year, he was officially named CEO of MGM Resorts International.
Hornbuckle was involved in the launch of The Mansion at MGM Grand and was a key player in the launch of MGM’s online gaming platform, BetMGM. Under Hornbuckle’s leadership, BetMGM became the official betting partner of multiple NFL teams: the Denver Broncos, Detroit Lions, Las Vegas Raiders, Tennessee Titans, Pittsburgh Steelers, and Baltimore Ravens. BetMGM then partnered with sports teams in other leagues: the Detroit Red Wings (NHL), Washington Nationals (MLB) and Philadelphia 76ers (NBA).