He did not finish his apprenticeship, but gained experience from the age of nineteen in 1589 as a surgeon with Lord Willoughby's regiment on its expedition to support the Protestant Henry IV of France and King of Navarre in his campaign against the Catholic League of Normandy.
In 1604, James I of England sent an embassy, led by Sir Thomas Smith, Governor of the East India Company, to Poland and possibly to Russia.
His duties were described as follows: Woodall's career then progressed rapidly with election as a surgeon at St. Bartholomew's Hospital in 1616 where he was a colleague of Sir William Harvey.
He suffered a setback, however, in 1625, when he served a writ on Sir Thomas Merry, a servant of the King who owed Woodall money.
He was briefly released to supervise surgeon's chests for the next fleet at the request of the East India Company, but was then jailed again, and only freed after issuing a contrite apology.