Barrick's CFO Catherine Raw will take over responsibility for the enlarged miner's US operations on January 1, in the newly-created position of COO for North America.
Barrick announced the appointment last week as it said its Barrick USA president Michael Brown, who has been with the company since 1994, would retire on December 31.
Barrick executive chairman John Thornton said Brown had worked tirelessly to connect Nevada's mining industry with government, communities and organisations across the state, always with an emphasis on building mutually beneficial, long-term partnerships.
Raw joined Barrick as executive vice president of business performance in 2015 and became CFO in April 2016.
She was previously co-manager of BlackRock's flagship mining funds.
Incoming CEO Mark Bristow, who is currently Randgold's CEO, recently said the enlarged company's four priorities would be the continued decentralisation of management, streamlining operations, developing core assets and selling non-core assets.
Shareholders of both companies agreed to the merger at meetings last month and it is expected to come into effect on January 1.
Barrick and Randgold both closed higher in Toronto and London respectively on Friday.
However Barrick shares have regained this year's earlier losses, up 0.22% year-to-date, while Randgold is down more than 10%.