In 1544, Howard accompanied the
Earl of Hertford's forces in the
invasion of Scotland. It was reported that he was hurt in the cheek by an English arrow during fighting on Edinburgh's
Royal Mile. In July of that year he took part in the
siege of Boulogne. On 27 May 1545, the King's Council ordered Howard to "repayre to serve uppon the sees". Later orders show that he detained several foreign vessels while patrolling the
English Channel. In May 1546, he was entrusted with the sum of £12,000 to pay the English army at Calais. In connection with these duties, he was referred to as "vice-admiral" to the then
Lord Admiral,
Viscount Lisle. When Lisle's attendance was required in May 1546 at negotiations which resulted in the signing of the
Treaty of Ardres on 7 June 1546, he turned command of the English fleet over to Howard. Howard's career received a check in 1547 with the downfall of his half-nephew
Henry Howard, Earl of Surrey. However, the setback was temporary. He was an ally of
John Dudley, 1st Duke of Northumberland, then Earl of Warwick, in his coup against the
Protector Somerset in October 1549, and on 19 March 1551, received the manor of
Effingham,
Surrey, and other properties by way of reward. On 29 October 1552, Northumberland secured Howard's appointment as
Lord Deputy and Governor of Calais, and in the same month he was sworn of the
Privy Council. When the young
King Edward VI died on 6 July 1553, Howard held Calais for
Queen Mary I against the supporters of her rival,
Lady Jane Grey. On 2 January 1554, he was appointed to meet the Spanish ambassadors who had come to London to negotiate a marriage between Queen Mary I and King
Philip II of Spain.
Wyatt's rebellion broke out on 25 January, and Howard was among those who raised the
militia to defend London. On 7 February 1554, he held
Ludgate, preventing the rebels from entering the city and leading to their surrender a few hours later. He was appointed to Queen Mary's Privy Council on 3 January 1554, and on 11 March, was created Baron Howard of Effingham. On 20 March 1554, he was granted a patent as Lord Admiral, replacing
Lord Clinton. On 9 October of that year, he was made a Knight of the Garter. Around this date, there was a masque at court, featuring mariners' costumes made of gold and silver cloth, which
Francis Yaxley thought was Howard's production. As Lord Admiral, Howard, with a fleet of 28 ships, met King Philip II on his arrival in England in 1555, and in August of that year escorted the King to
Flanders. In 1557 Howard's fleet transported a force under the command of the
Earl of Pembroke to Calais. Lord Howard's support for the accession of his great-niece,
Elizabeth, exposed him to suspicion, although he was never considered disloyal by Queen Mary. In February 1558 Howard's patent as Lord Admiral was revoked, and on 12 February 1558, the office was restored to Lord Clinton. Howard was compensated by a grant of the
reversion of the office of
Lord Chamberlain of the Household and an annuity of 200 marks, effective the previous September. ==Landholdings==