Neal joins in September from commercial real estate firm Land Securities Group, where she is head of corporate communications. Kemp, who was head of UK corporate communications, left the company in May.
Neal is the third senior appointment to National Grid's communications team in the past year following group director of brand and social purpose Jeremy Ruane and group corporate affairs director Barney Wyld.
She will be responsible for driving the group narrative across National Grid’s operations in the UK and US, bringing together all external corporate affairs activities.
Her role also involves overseeing media relations and executive profiling, and she will be National Grid's lead spokesperson to the media. She will report into Wyld and joins the corporate affairs leadership team.
"National Grid is at the forefront of ensuring a healthier, greener energy future for Britain and the US, combining the best of British engineering with smart technology to deliver cleaner, lower cost renewables to power our homes, our travel, and our work," Wyld said.
"We have a great story to tell, and with her wealth of experience across journalism and corporate communications we look forward to Molly helping us raise our game."
Neal added: "I am excited to be joining National Grid at this pivotal moment. As a leading electricity and gas utility business in the UK and US, National Grid has a unique role to play in the drive to reduce emissions and I look forward to shaping and sharing that vision."
At Land Securities Group, Neal helped the company rebrand and "streamlined its digital estate". She was also chair of the company’s diversity and inclusion committee and founded its women's network.
Earlier in her career, Neal spent eight years in journalism and was a columnist and editor at the Wall Street Journal.