Adds new 18 U.S.C. 5032A, "Modification of an imposed term of imprisonment for violations of law committed prior to age 18," establishing (1) judicial authority to reduce terms of imprisonment for defendants convicted as adults of offenses committed before age 18 who have served at least 20 years and whom the court finds not a danger and that interests of justice warrant modification; (2) a supervised release term of not less than 5 years for any reduction; (3) factors the court must consider; (4) limits on repeat applications and timing for second and final applications; (5) procedures including BOP notice after 19 years, crime-victim notifications, filing and hearing rules, right to appointed counsel if needed, and appeal governed by FRAP 4(a); and (6) protection of access to educational, training, and rehabilitative programs for eligible defendants.

Replaces section 5031 with a revised set of definitions governing terms in the chapter (defines terms including adjudication, conviction, destroy, expunge, expungement hearing/petition, high-risk public trust position (referring to 5 C.F.R. 731.106(b)), juvenile (including special rule up to age 21 for chapter proceedings), juvenile delinquency (including reference to section 922(x)), juvenile nonviolent offense (separate definitions for dismissed/not-delinquent arrests and delinquency adjudications), juvenile record (detailed list of included records and explicit exclusions for fingerprints and DNA), petitioner, seal, sealing/expungement hearings and petitions).

Makes targeted textual amendments to 18 U.S.C. 5038: (1) in subsection (a) inserts additional text in the flush text following paragraph (6); and (2) in subsection (b) strikes the phrase "District courts exercising jurisdiction over any juvenile" and replaces it with revised language (replacement text not shown in excerpt).

Amends subsection (b) of 21 U.S.C. 841 by replacing references to 'felony drug offense' with 'serious drug felony or serious violent felony' in paragraph (1) (subparagraphs (C), (D), and (E)(ii)), paragraph (2), and paragraph (3).

Amends 21 U.S.C. 960(b)(3) by striking 'felony drug offense' and inserting 'serious drug felony or serious violent felony'.

Redesignates existing subsection (g) as subsection (h) and inserts a new subsection (g) titled 'Inadequacy of criminal history' which authorizes a court, upon prior notice to the Government and with written specific reasons, to waive the subsection (f)(1) criminal-history requirement when reliable information indicates that excluding the defendant under (f)(1) would substantially overrepresent the defendant's criminal history or likelihood of reoffense; the new subsection (g) also prohibits the waiver for defendants convicted of a serious drug felony or a serious violent felony.

Adds new section 5044 to title 18, U.S.C., establishing procedures for sealing juvenile records (including notice, sealing orders, law enforcement access rules, transition periods, prohibitions and penalties for unauthorized disclosure).

Adds new section 5045 to title 18, U.S.C., establishing procedures for expungement of juvenile records (automatic expungement, petitioning process, verification, limitations, and duties to notify entities holding records).

Amends the table of sections for title 18, U.S.C., by adding at the end a new chapter 403 to reflect the added sections.

Amends section 534 of title 28, U.S.C., by adding subsection (g) ('Ensuring accuracy of Federal criminal records'), defining terms, requiring Attorney General procedures for correcting or verifying records, setting timelines for obtaining dispositions and investigating challenges, prohibiting certain exchanges, and authorizing fees and reporting/regulatory deadlines.