The contract, worth £100m covers management and maintenance of more than 2,000 vehicles across 800 sites for Jewson owner Saint-Gobain.
The ten-year deal that includes the UK and Ireland comes after a two-year tendering process.
Rushlift chairman, Peter Cosgrove says: "It is one of the largest contracts in the industry and from our point of view it is transformational.
"The agreement is on an unprecedented scale and we are excited by the opportunities and challenges it presents our business. It's a superb vote of confidence in our business values and approach."
"We were up against all the major firms in the industry, a lot of them bigger than us," he says.
Saint-Gobain fleet director, Ian Berrill, says: "Having the UK's largest fleet has many benefits but also many challenges. Being able to manage the fleet makeup, control costs and respond to our changing needs is crucial."