He left the Public Service to establish a company, Moteliers, to establish a chain of motels, several designed by Franca and Enrico Taglietti: the Town House Motels in Canberra (opened 1961), and Wagga Wagga (opened 1963), then sold the company.
Taglietti also designed a café and facilities block for Killen's next project, the Sundown drive-in.
He opened As managing director of Cinema Center Services Pty Ltd, he began importing (especially French) films himself rather than rely on commercial distributors.
[6] Killen was an early proponent of a light rail service between Canberra and its northern suburbs.
[7] Killen married Dinny in 1960, and established a property in the Majura Valley, and in conjunction with Dr Edgar Riek planted with chardonnay, pinot noir, merlot and cabernet sauvignon grapes, as the Mount Majura Vineyard, managed by Dinny Killen.