Marshal James McFarland's military career included a decade-long stint with the AFFC's Department of Strategy and Tactics, during which time he attached himself to several different field units where he saw substantial action. He was attached to the Tenth Lyran Guards when they were driven off Alyina by Clan Jade Falcon in 3051 and later was permitted to observe Precentor Martial Anastasius Focht's headquarters during the Battle of Tukayyid. He was personally chosen by Archon-Prince Victor Steiner-Davion to command the Tenth after the retirement of Hauptmann General Kaulkas after the Clan Invasion.  McFarland therefore took part in Operation Bulldog and journeyed to the Clan Homeworlds alongside Prince Victor, where the Tenth's reputation as a crack unit was only reinforced.
At the start of the FedCom Civil War in late 3062, the Tenth Lyran Guards were effectively stranded on Robinson, stripped of their JumpShip assets. McFarland was finally able to commandeer enough transport in early 3065 to leave Robinson, jumping to the Kentares system on the first leg of their trek to Tikonov, where Victor's task force was engaged in fighting the loyalists. Unfortunately for MacFarland, DMI agents sabotaged several of the Tenth's JumpShips, forcing them to remain in system for several weeks while technicians began repairs. While this was taking place, Kentares was under attack by the Draconis Combine's 3rd Benjamin Regulars. Kentares was under-defended, protected only by a hastily rebuilt Kentares DMM, assembled from elements of the 5th Donegal Guards and the Clovis DMM. With the defenders quickly falling back against the Kuritans, McFarland chose to intervene, landing on Kentares and engaging the Third. The Tenth Lyran and Kentares DMM destroyed the Regulars in a week of hard fighting. McFarland personally saw to it that DCMS prisoners taken were treated properly. 
The Tenth eventually linked up with Victor, and in late May of 3066, they finally assaulted Tikonov, alongside ComStar's 244th Division relieving the 6th Crucis Lancers, who had been fighting on Tikonov for years. The Tenth and 244th easily crushed the 3rd Republican Guards when their armored infantry assets eliminated the Guards' command structure. The Allies then turned on the capital city of Tikograd, where they destroyed a detachment of the Valexa CMM. The 15th Deneb Light Cavalry was forced to withdraw, and Tikonov was finally in the hands of the allies.
It had long been almost inevitable that the Civil War in the Federated Suns would come down to an assault by the allies on New Avalon, the seat of Katherine Steiner-Davion's power. On November 8, 3066, Victor, McFarland and the rest of their task force arrived on the capital planet. Though it took several months and the Tenth took heavy losses, the allies eventually prevailed on April 20, 3067, when Katherine finally surrendered.
Like the rest of the Tenth, McFarland chose to remain on New Avalon after the Civil War as part of the new Armed Forces of the Federated Suns. As of August 1, 3067, McFarland remained in command of the Tenth on New Avalon, with his force operating at around 35 percent capacity. 
In December 3067, the Word of Blake launched its Jihad on the Inner Sphere. While WarShips bombarded the planet, the 31st Division landed on-planet and advanced on Avalon City. McFarland and the Tenth were the first unit to oppose the Blakists, engaging them at McCarel Farm. Despite being under-strength, the Tenth managed to inflict significant damage on the Thirty-first before they were forced to pull back. They bought the defenders enough time to regroup and hold the capital city against the invaders. 
Unfortunately, casualties to the Tenth were too heavy to make them an effective independent fighting force, and by February 3068 they were merged into the 1st Davion Guards.  It is unclear if McFarland survived the fighting on New Avalon.
- Field Manual: Lyran Alliance, p. 78, "10th Lyran Guards RCT: The Revenants"
- FedCom Civil War, p. 137, "Kentares IV"
- FedCom Civil War, pp. 158-159, "Tikonov"
- FedCom Civil War, pp. 170-171, "New Avalon"
- Jihad Turning Points: New Avalon, p. 6, "Combatants: Tenth Lyran Guards"
- Field Manual: Updates, p. 179, "Lyran Alliance Armed Forces Deployment Table"
- Jihad Turning Points: New Avalon, p. 8, "Unwelcome Guests"