Who painted this?

Frans Hals the Elder (1582 – 1666) was a Dutch Golden Age portrait painter who lived and worked in Haarlem. He is notable for his loose painterly brushwork, and he helped introduce this lively style of painting into Dutch art. Hals played an important role in the evolution of 17th-century group portraiture.

The picture in the question is "The Laughing Cavalier," a 1624 portrait by Hals, now held by the Wallace Collection in London. It is considered one of the most brilliant of all Baroque portraits. The title is an invention of the Victorian public and press, dating from its exhibition in the opening display at the Bethnal Green Museum in 1872–75, just after its arrival in England, after which it was regularly reproduced as a print, and became among of the best known old master paintings in Britain. The unknown subject is in fact not laughing, but can be said to have an enigmatic smile, much amplified by his upturned moustache.