10 U.S. Code § 1599e - Probationary period for employees

(a) In General.—
Notwithstanding sections 3321 and 3393(d) of title 5, the appointment of a covered employee shall become final only after such employee has served a probationary period of two years. The Secretary concerned may extend a probationary period under this subsection at the discretion of such Secretary.
(b) Definitions.—In this section:
(1) The term “covered employee” means any individual—
appointed to a permanent position within the competitive service at the Department of Defense; or
appointed as a career appointee (as that term is defined in section 3132(a)(4) of title 5) within the Senior Executive Service at the Department.
The term “Secretary concerned” includes the Secretary of Defense with respect to employees of the Department of Defense who are not employees of a military department.
(c) Employment Becomes Final.—
Upon the expiration of a covered employee’s probationary period under subsection (a), the supervisor of the employee shall determine whether the appointment becomes final based on regulations prescribed for such purpose by the Secretary of Defense.
(d) Application of Chapter 75 of Title 5 for Employees in the Competitive Service.—
With respect to any individual described in subsection (b)(1)(A) and to whom this section applies, section 7501(1) and section 7511(a)(1)(A)(ii) of title 5 shall be applied to such individual by substituting “completed 2 years” for “completed 1 year” in each instance it appears.
Effective Date

Pub. L. 114–92, div. A, title XI, § 1105(b), Nov. 25, 2015, 129 Stat. 1024, provided that:

“The amendment made by subsection (a) [enacting this section] shall apply to any covered employee (as that term is defined in section 1599e of title 10, United States Code, as added by such subsection) appointed after the date of the enactment of this section [Nov. 25, 2015].”