Serghei Railean had studied at the Republican Colleague of Informatics and Law and at the Economic Sciences Academy (international economic relations) before getting hired as a credit settlement specialist at Micro Enterprise Credit Moldova, part of the international financial group ProCredit.

In 2001 through 2004 Mr. Railean worked as a senior projects coordinator at Citizens Network for Foreign Affairs Inc.(CNFA), a USAID-funded program. Until 2006 he worked in Romania at Mechel Campia Turzii SA (in Cluj County), first as a financial auditor and later as a deputy manager general for economic and financial issues. Mechel Campia Turzii SA is part of the Mechel Group of Russian billionaire Igor Zyuzin.

In 2006 Mr. Railean took over as the financial director at the state-run (until 2019) cigarette manufacturer Tutun-CTC in the Moldovan capital. He served since 2008 under the management of Pavel Filip, the prime minister under the Democratic Party rule until 2019. In 2011 Pavel Filip was appointed the minister of information technology and communication and his subordinate Serghei Railean took over as the director-general of Registru, a governmental agency for information resources under the watch of the Ministry of Information Technology and Communication.

When Registru became part of the Public Services Agency in 2017, Raileanu headed the new institution. When the Democrats lost the power in July 2019, Mr. Raileanu got sacked. In March 2020 the Democrats joined the Socialists to form a new government and Serghei Raileanu was hired as the minister of economy and infrastructure.