The tech giant's class A stock passed the milestone in intraday trading, hitting as high as $1,007.40 per share.
The movement higher comes less than a week after Amazon broke through that barrier amid a boom in tech stocks, in particular FAANGs - Facebook, Apple, Amazon, Netflix and Google.
US tech stocks have jumped almost 20 per cent this year while the S&P 500 has gained eight per cent, recent analysis by the FT found.
All the FAANGs bar Alphabet are up more than 300 per cent this year. Alphabet is up by more than 25 per cent.
Alphabet is likely to have been pushed higher on a note from Pacific Crest in which analyst Andy Hargreave said Google was a better buy than Apple.
Shares in Apple dipped around one per cent lower at the US markets open as the firm downgraded it to sector weight from overweight.
CNBC reports the note said: "We believe Apple anticipates strong performance in the iPhone 8 cycle, while providing relatively little weight to risks through the cycle or the potential for iPhone sales to decline in full-year 2019."
The knock comes as Apple is expected to announce its latest software at its developer conference WWDC and where the unveiling of an Amazon and Google rival smart speaker is on the cards.