Sawhney led Citi's global and regional investor services teams for the last 15 years, having joined the firm in 1992 and holding numerous roles within the firm's securities services business.
He also worked as head of worldwide securities services and managing director of JP Morgan Bank in Luxembourg before returning to Citi, where he focused on servicing the global asset manager and asset owner industries.
Link Fund Solutions sale edges closer to completion after key condition satisfied
His appointment followed the announcement in August that Waystone's acquisition of Link Fund Solutions was still on schedule to close later this year, subject to regulatory approvals moving forward.
It also came after the sudden exit of the firm's chief executive Derek Delaney, chief financial officer Glen Magee and chief operating officer Paul Cahill in March this year, which the firm said was "in no way linked to anything of a financial or regulatory nature".
Waystone said the acquisition, which will see a further 600 staff join the business, will "significantly strengthen" its offering to clients in the ACD and administration space, as well as its ability to provide "strength and depth" in its offering to investment managers and sponsors.
"It is a credit to the entire Waystone team that we have been able to attract a CEO of Sanjiv's calibre," said Nancy Lewis, Waystone's executive chair. "His global experience and track record of managing large teams through significant phases of growth is something we will all be able to draw upon."
Link Fund Solutions sale in doubt after Waystone Group senior management exit
Sawhney added: "The world of investor services has become far more complex and international over the last few years, and the expectations placed upon service providers are therefore so much higher.
"With its global reach, and with such a breadth of expertise across so many verticals, Waystone is well-placed to increasingly provide expert advice, and I look forward to playing my part in the continued growth of the business."