Legally Binding Budget Act of 2011 - (Sec. 2) Amends the Congressional Budget Act of 1974 (CBA) to require joint budget resolutions signed by the President instead of the concurrent resolutions now required (which do not have to be signed by the President).
(Sec. 4) Prohibits the consideration of budget-related legislation before the joint budget resolution becomes law. Makes a conforming amendment to the Congressional Budget and Impoundment Control Act of 1974.
(Sec. 5) Permits revisions of joint budget resolutions already enacted. Authorizes the chairs of the congressional budget committees to adjust budgetary levels and allocations as needed for enforcement of budget resolutions.
(Sec. 6) Makes it out of order in both chambers to consider any joint budget resolution, amendment, or conference report that contains certain matter prohibited by the CBA, particularly inclusion in the surplus or deficit totals of any outlays and revenue totals of the Old Age, Survivors, and Disability Insurance (OASDI) program under title II of the Social Security Act.
(Sec. 7) Considers the aggregates, allocations, and any other matters that pertain solely to Congress specified in a joint budget resolution as enforceable upon enactment, or 15 days following presentment to the President, whichever occurs earlier. (Thus creates automatic congressional enforcement of a joint budget resolution.)
(Sec. 9) Makes conforming amendments to: (1) the Rules of the House of Representatives, and (2) the Balanced Budget and Emergency Deficit Control Act of 1985 (Gramm-Rudman-Hollings Act).