Senate Majority Leader Harry Reid (D-Nev.) said it was important that Congress act on the reform bill as quickly as possible to give McDonald and his team "the resources they need to ensure American veterans are getting the care we've promised them."
Senate Republican leader Mitch McConnell of Kentucky said McDonald "has a tough job ahead of him," but said that if he "is willing to work in a collaborative and open manner with Congress," Republicans will help McDonald fix the VA.
President Barack Obama applauded McDonald's confirmation.
"As a veteran himself and a proud member of a military family, Bob is deeply committed to serving our veterans and their families," Obama said in a statement. "And as an executive with decades of private-sector experience, he is uniquely equipped to lead the Department of Veterans Affairs, and to help change the way the VA does business."
House and Senate negotiators have approved the VA overhaul bill, which is co-sponsored by Rep. Jeff Miller (R-Fla.) and Sen. Bernie Sanders (I-Vt.). Miller chairs the House Veterans Affairs Committee, while Sanders chairs the Senate panel. A vote by the 28-member conference committee late Monday sent the bill to the full House and Senate, where approval was expected later this week.
The measure includes $10 billion in emergency spending to help veterans who can't get prompt appointments with VA doctors to obtain outside care; $5 billion to hire doctors, nurses and other medical staff; and about $1.5 billion to lease 27 new clinics across the country.
Miller and Sanders say the bill will require about $12 billion in new spending after accounting for about $5 billion in unspecified spending cuts from the VA's budget.
Despite the steep cost, Miller said he is confident he can sell the bill to fellow Republicans, including tea party members.
"Taking care of our veterans is not an inexpensive proposition, and our members understand that," he said. "The VA has caused this problem and one of the ways that we can help solve it is to give veterans a choice, a choice to stay in the system or a choice to go out of the system" to get government-paid healthcare from a private doctor.
Rep. Tim Huelskamp (R-Kan.), a tea party favorite and a member of the House veterans panel, said "throwing money at the VA won't solve their problem," adding that "a fundamental change in culture and real leadership from the president on down is the only way to provide the quality, timely care our veterans deserve."
Sen. Patty Murray (D-Wash.) said McDonald is faced with "a truly monumental task" as he takes over an agency that provides healthcare to nearly 9 million enrolled veterans and disability compensation to nearly 4 million veterans.
Even if Congress passes the compromise reform bill, the VA faces a host of other serious challenges, including a high suicide rate among veterans and treatment for thousands of veterans coping with sexual assaults, said Murray, a former Veterans Affairs chairwoman.
The VA also faces "an uphill battle" as it works to eliminate veterans' homelessness and a lengthy backlog for disability claims, Murray said. "Mr. McDonald will have to grapple with these, and many more issues, all on day one," she said.
McDonald said at a confirmation hearing last week that he intends to act quickly "to deliver the needed reforms our veterans deserve."
His plans include laying out a veterans-centered vision for the department and improving communication within the vast agency, which includes more than 300,000 employees in all 50 states and the District of Columbia. McDonald also said he will host frequent video conferences with employees and travel to field offices around the country.
A former Army Ranger, McDonald said taking care of veterans is personal for him. His father served in the Army Air Corps after World War II, and his wife's father was shot down over Europe and survived harsh treatment as a prisoner of war. Another relative was exposed to Agent Orange in Vietnam and receives care from the VA, McDonald said.
Sen. Thad Cochran (R-Miss.) initially voted against McDonald, then changed his vote to a yes.