Holbein's preparatory drawing for the portrait survives at Windsor, made in coloured chalks, pen and ink and metalpoint on paper prepared with a pink ground^[1]. It is inscribed with Southwell's age, thirty-three, and turned at a right angle so Holbein could add a note in German recording that his eyes were a little yellow^[1]. The finished panel follows the drawing closely, including a small adjustment to the back of the neck, and the drawing supplied the exact positions of scars left on Southwell's neck and face by tuberculosis, which the painter carried through into the panel without softening them^[1]. The silhouettes of the buttons on Southwell's sleeve are matched precisely between drawing and painting, even though the red chalk stripes of the sleeve itself were dropped^[1]. Southwell's chain is only outlined, and the badge on his hat was left blank, probably because Holbein intended a separate study for it, a step he is known to have taken for other sitters' badges^[1]. Faint reinforcement in metalpoint over the drawn outlines shows where the design was later transferred through to the panel^[1].

Southwell was born around 1503 or 1504, of Norfolk origin like several of Holbein's English sitters^[1]. He built a career as a member of parliament, an administrator and a diplomat, and by reputation held religious views that were conservative for his time^[1]. That did not stop him working closely with Thomas Cromwell, the king's chief minister and the architect of the break with Rome^[1]. From 1535 Southwell took part in the suppression of England's monasteries, the campaign that closed religious houses across the country and redirected their wealth to the crown^[1]. In 1536, the year Holbein painted this portrait, Southwell was appointed receiver for the Court of Augmentations, the office created specifically to handle the proceeds of the dissolution^[1]. The precision of the date inscribed on the painting is unusual among Holbein's English portraits, and its exact significance is not recorded, though it places the picture squarely at the point in Southwell's career when his new office made him one of the more consequential administrators in the country^[1].

Southwell is shown half length, seen almost in profile, a pose Holbein used for a number of sitters connected with Parliament and the court in these years^[3]. His hands rest near a glimpse of a brilliant red tablecloth, one of the few passages of strong colour in an otherwise dark and restrained picture^[1]. Holbein's handling of Southwell's coat, in black silks and satins, and the transitions between shadow and highlight in the painted flesh, increase the sense that the sitter occupies the same space as the viewer rather than a separate, staged world^[1]. On his hat, Southwell wears a badge showing the bust of a Moorish woman worked in gold and agate, a piece of jewellery precise enough that it could plausibly have existed as an object rather than an invention for the picture^[1]. Holbein's paintings of this period generally follow this same formula: the half length figure filling the frame, an identifying inscription at the side of the head, and little else to distract from the sitter^[3].