"A little bit of handshaking and backslapping going on back here," Mr Halsell reported, "and this is just the first of several exciting days."
The crew are on a mission to repair the unoccupied station, which needs new batteries and a boost into a higher orbit.
Commander James Halsell Jr guided Atlantis to a smooth link-up, 207 miles above the Earth.
The station gleamed as the shuttle made its final approach - Mission Control in Houston called it "a beautiful sight."
"A little bit of handshaking and backslapping going on back here," Mr Halsell reported, "and this is just the first of several exciting days."
Mr Halsell and his six crew members, including a Russian cosmonaut, are the first space station visitors in a year.
Flight controllers in Houston and Moscow prepared the station for their arrival by turning up the thermostat in the chilly outpost and cleaning its stagnant air.
Despite the urgency of the work, the hatches between the two spacecraft will remain sealed until Monday night.
The crew's first job will be to conduct a spacewalk on Sunday night.
Launch delayed
The shuttle launched at dawn on Friday after weeks of delay.
Building work on the $60bn station has fallen behind schedule and the orbiting platform also requires repairs to elements already constructed.
The crew will have to replace four of six malfunctioning solar-charged batteries.
They will also use the shuttle's engines to boost the station's falling orbit as it is dropping by about 2.4km (1.5 miles) a week.
The astronauts will also replace fire extinguishers, smoke detectors and fans that have exceeded their certified lifetime.
Setback
Nasa had not expected visiting shuttle crews to do so much maintenance work. It was expected to be taken care of by residents of the space station.
But Russia pushed back the date for moving in until November at the earliest.
They are two years behind schedule in launching the station's crucial service module, needed for guidance, navigation and life support.
The Russian service module would make the station habitable and ISS managers hope to have the first three-member expeditionary crew in residence by the end of the year.
The shuttle is scheduled to return to Earth on 29 May.