He entered the Society of Jesus and was sent to the East. He landed at Macao in 1610, and while waiting a favourable opportunity to penetrate into China busied himself for three years in teaching mathematics.
His thirty years' residence in China was marked by unceasing zeal and considerable success. He adopted the dress and manners of the country, was the first Christian missionary in Kiang-si, and built several churches in Fujian. He wrote in Chinese a life of Christ (Pekin, 1635-1637, 8 vols.; often reprinted, e.g. in 1887 in 3 vols., and used even by Protestant missionaries) and a cosmography (Iche fang wai ki Hang-chow, 1623, 6 vols.), which was translated into Manchu under the title The True Origin of 10,000 Things, a copy of which was sent from Beijing to Paris in 1789. Alenio died at Fuzhou in 1649.
He was called "Confucius from the West". He was known to the Chinese people as 艾儒略.