On the 6th of May 1568, Angus McConnell, as heir of his father received a precept of Clare Constant in Ardnamurchan, and on the 10th of October, 1570, he received a precept of infiefment dated at Duart, as heir of his brother Archibald.
On the 23rd of April, 1573, the great Turlough Lynagh O'Neill, successor of Shane O'Neill, visited Edinburgh and it is recorded that he lodged "ane complaint aganis Angus MacConeil becus he wold not be subdewit to the Earl of Argyle," O'Neill's stepson. However, at this time Clan Iain Mhoir appears to have recovered its former glory and nothing appears to have come of the complaint.
Angus visited Sir Laughlan Maclean to attempt to settle a quarrel. Maclean took him prisoner and detained him until he renounced his right to the Rhinus of Islay, requiring him to leave his son James and brother Ranald as hostages.
Sir Lachlan went to take sesine of the lands in July, 1586, taking with him his hostage James McConnell, the heir to Dunnyveg, and leaving Ranald, the other hostage, in irons in Duart Castle. Angus extended to Sir Laughlan an invitation to visit him at Mullintrae, which was accepted. After a banquet, Sir Laughlin, together with his hostage, James McConnell and eighty-six of his me, were housed next to Angus' castle. Angus gather three or four hundred of his retainers and then called Sir Laughlan out to have his sleeping draught. But McLean, being suspicious, refused to come out. After repeated demands, Sir Laughlin, taking the hostage James McConnell on his shoulders, came to the portal of his abode. James was required to ask that Angus, his father, spare the life of Sir Laughlan, his uncle. Angus finally relented, but left Sir Laughlan a prisoner, together with all his men.
A kinsman of Duost circulated a false report that Ranald McConnell, the hostage of Sir Laughlan who had been left in chains in Duart Castle, had been murdered. It is said that two of the MacLean prisoners were killed each day until only Sir Laughlan and his uncle John Dubh of Morvern remained. These survivors were finally released although hostages were taken by Angus and his brother Ranald was released before the liberty of these survivors was granted. Angus was pardoned for this offense by the King.
The King entreated the Earl of Huntly to restrain the lawlessness of these Highlanders. On April 20, 1587, he commissioned Huntly for this purpose but reserved the Chiefs of Dunnyveg and Duart to his own royal influence as he states: "For we have written effectuously to Angus McConnell and hes spoken with MacClane, being heir for the same effect." This, however, proved to be but a lull in the storm and hostilities continued until 1591 when both Duart and Dunneyveg were invited to Edinburgh by the King, where they were both confined. In 1592, Angus was set at liberty under certain conditions, but was required to leave his son James McConnell with the King as a hostage.
Angus failed to keep the terms of his pardon and in June, 1593, he was summoned for treason and a sentence of forfeiture was imposed. In 1596 the King again moved against him, but Angus again made his peace with the King, one of the terms being: "That James McConnell (Angus' son) shall remain with him (the King) at Court and not depart till he be relieved by his Highness."
Angus again regretted his submission and again assumed control of his property. In a quarrel with the Laird of Loupe, he was captured and his son James McConnell assumed command of the Clan Iain Mhoir.
While at Court as a hostage, James McConnell became quite a favorite and was knighted by the King. After he assumed control of affairs of the Clan during the incarceration of his father, Sir Laughlan Maclean rened his feud with Dunnyveg and claimed all of Isla. In 1598 Sir James McConnell offered him a compromise, but it was refused. A fierce battle was fought between their respective forces at a place called Traigh Ghruinneartt. Dunnyveg's forces were outnumbered, but they defeated the Macleans and Sir Laughlan, eighty of his kinsmen, and two hundred of his common soldiers were killed.
Sir James McConnell was shot through the body with an arrow and left on the field. However, he was later discovered and restored to health. James McConnell offered terms of submission to the crown which were approved; but the Earl of Argyle, who espoused the Maclean cause in this quarrel, opposed their acceptance and the compromise fell through.
Sir James refused to surrender control of affairs to Angus McConnell, his father, who had by this time, 1603, regained his liberty. With the assistance of the Campbells he captured Sir James and confined him in Blackness Castle. Sir James attempted to escape and was sent to Edinburgh Castle.
Angus in 1606 attempted to compose his differences with the King, but Argyle, who controlled the Privy Council, plotted against him, and blocking the compromise, proposed himself as tenant of the crown for the lands in Kintyre. In 1607 Argyle prevailed and the lands of Dunnyveg in Kintyre and the island of Jura were confirmed to him. In July 1607 Argyle took possession of these lands and Angus was forced to flee to Ireland.
On August 4, 1609, Dunnyveg Castle was surrendered by Angus Og to Lord Ochiltree who was acting for the Privy Council. On January 1, 1612 Angus McConnell surrendered his title to all his estates to Sir John Campbell on payment of 6,000 merks. Angus appears to have spent his latter days with the Stewarts of Bute. He died in Rothesay on October 21, 1614 and was buried at his old Castle of Saddel.
He had married Mary, daughter of Hecter Og Maclean of Duart and had by her:
1. James McConnell, who is usually considered his successor.
2. Angus Og McConnell, who married Katharine, daughter of Duncan Campbell of Danna. He had two sons of whom nothing further is known. He was most treacherously executed in Grassmarket, Edinburgh, July 8, 1675.
3. Alexander Og McConnell, who was drowned at Caol Isle, October 3, 1613, without leaving lawful heirs.
4. Mary McConnell, who married Sir Donald Macdonald of Clanranald.
5. Margaret McConnell, who married Ranald Macdonald of Benbecula.
6. Annabell McConnell, who married Archibald Macdonald of Largie.
Is has been seen that Sir James McConnell was in prison at the time of his father's death and that Clan Iain Mhoir had been deprived of all its priveleges as a reigning house. However, it is usually considered that Angus was succeeded by his oldest son, Sir James McConnell.