I don't see a "Jack Lacey" per se as a captain in any Virginia regiment but I do find this "Lacy":
John F. Lacy (First_Last)
Regiment Name 44 Virginia Infantry.
Soldier's Rank_In 2 Lieutenant
Soldier's Rank_Out Captain
Film Number M382 roll 32
44th Regiment, Virginia Infantry
44th Infantry Regiment was organized in June, 1861, with men from Richmond and Farmville, and Appomattox, Buckingham, Louisa, Goochland, Amelia, Fluvanna, and Hanover counties. The unit fought at Rich Mountain, in Lee's Cheat Mountain Campaign, and was active in Jackson's Valley operations. During March, 1862, it was reduced to nine companies as Company A was transferred to the artillery. The 44th served in General Early's, J.R. Jones', and W. Terry's Brigade, Army of Northern Virginia. It was involved in many engagements from the Seven Days' Battles to Cold Harbor, then continued the fight with Early in the Shenandoah Valley and around Appomattox. The regiment reported 5 wounded at Greenbrier River, had 2 killed and 17 wounded at McDowell, and lost 15 killed and 38 wounded at Cross Keys and Port Republic. It sustained 15 casualties at Fredericksburg and 71 at Chancellorsville, and of the 227 engaged at Gettysburg more than twenty percent were disabled. Only 1 officer and 12 men surrendered in April, 1865. The field officers were Colonels Norvell Cobb and William C. Scott; Lieutenant Colonels Thomas R. Buckner, James L. Hubard, A.C. Jones; and Major David W. Anderson.
While it does not list King William as its source of manpower, there are two (2) Lacy's connected with Company B. The first Captain was William S. Lacy. The second, John Archibald Fleming Lacy, retired as of August 1, 1864.
Company B was called the Byrd Rifles or Goochland Byrd Rifles, enlisted April 1861, mustered June 3, 1861 for 1 year; reorganized May 1, 1862.