In November last year, both Hiney and the joint managing director, Suzanne Partridge, lost their jobs at HTW as part of an agency restructure under the new management of the chief executive, John Butler.
In his new role, Hiney will be responsible for Carlson's operations across its three UK offices. He will report to the senior vice-president EMEA, Jonathan Harman, who joined the agency from RMG Connect in November last year.
This is the second significant hiring since Harman joined the agency. Mark Attrill was named as the creative director a week ago.
In his previous role at HTW, Hiney was responsible for the integration of HTW and Wunderman Interactive. Before HTW, he held the position of the business director at Rapier. He also spent time at Modem Media and Tequila\.
Harman said: "Hiney is a client-focused leader with a track record in getting business results for his clients. He's a great fit with what we're trying to achieve at the agency, culturally and with clients."
Hiney added: "Carlson has all the right parts. With Jonathan's experience and passion, as well as the fired-up attitude that Carlson has about the customer journey, I'm looking forward to getting started."
The expansion of the senior management team comes after the agency picked up the brief to handle Coca-Cola's new loyalty scheme, which is aimed at the teenage market.