Crow will be responsible for Sky Media's direct response trading, including the targeted ad format AdSmart. Crow will report to Jonathan Robertson, the head of results-based trading at Sky Media.
Crow has been at MediaCom since 1993 and is currently the head of direct response TV at the WPP media agency. She will join Sky Media in September.
John Litster, the managing director of Sky Media, said: "Sky Media has a market-leading capability in response trading, which was further consolidated by our acquisition of [the software provider] Virtuous Systems last year.
"With over 20 years' experience, Cath has unparalleled expertise in this field."
In his new role, Ben Louis will manage sales across WPP media agencies, including MediaCom, Maxus, MEC, Mindshare and M/SIX. He will report to Duncan Wynn, the director of sales.
With 20 years of sales experience at ITV and its former sales houses, Louis has been a group sales controller managing a cross-media sales team since 2011. His previous roles include key account director and planning controller.
Louis started his career at TSMS in 1992, before moving to Granada in 2000.
Litster said: "Ben, too, is highly regarded throughout the industry, with rare blend of skills that sit perfectly with Sky Media's approach to the market. He is commercially astute and thinks creatively across a portfolio of advertising platforms.
"We're delighted to welcome them both to Sky Media to help us to continue to lead the way in offering media agencies and advertisers a range of opportunities not available via any other sales house."