[2] On 31 January 1804, Wightman entered Lincoln's Inn, and, after some years of practice as a special pleader, he was called to the bar in 1821.

He was known as a sound and clear-headed lawyer, and for several years held the post of junior counsel to the treasury.

In 1830, Wightman was appointed a member of the commission of 1830 upon the practice of the common law courts.

[3] He was engaged in many celebrated cases, particularly the prosecutions arising out of the Bristol riots; but, owing to an almost excessive modesty, was little known except to his profession.

In February 1841 he was promoted to a judgeship of the Queen's Bench, on the resignation of Mr Justice Joseph Littledale, and was knighted on 28 April, and here he served as a judge for nearly 23 years.