He is the centrepiece of an overhaul to Irish's pack, with Scotland international Geoff Cross also arriving to strengthen the front three.
And Smith insists Court can make a big impact right from the off when the season starts in September.
"Halani (Aulika) coming back is like a new signing for us and Tom Court's a big, big loosehead who is a great strength for us," said Smith. "Geoff Cross played really well against South Africa for Scotland last month, so in the front-row we've added a lot of quality.
"So we've put a big emphasis on getting the tight five sorted but also adding more strength and depth to the back-row.
"We're in pretty good shape - like all teams we want to get a fast start but we also recognise it's a 22 round competition played over nine months, so you've got to have endurance as well."