Day one as a new EU staff member is more disorienting than most newcomers expect. The institutions are large, the procedures are formalised, the cultural codes are subtle, and the file you're meant to take over usually has 18 months of context locked in inboxes you haven't yet been granted access to. The first 90 days are when you build the habits, relationships, and reputation that will carry your career inside the institutions for years. Use them deliberately.
Week one: paperwork, badges, mandatory training
Your first week is mostly administrative. You'll complete onboarding paperwork with HR (employment contract or appointment decision, social security registration, family allowance forms, expatriation allowance certification), receive your access badge and IT credentials, take the mandatory cybersecurity and data-protection training, and meet your unit. Don't try to be productive on substantive work yet — there will be time. Use the bandwidth to read the unit's annual work programme, the most recent two or three Commissioner speeches in your policy area, and any handover note your predecessor left.
If you're moving country to take the role, deal with the practical relocation logistics in parallel: register with the local commune (Brussels, Luxembourg, Frankfurt, etc. all have specific procedures), set up a local bank account (some institutions have arrangements with specific banks for staff), get your local mobile number, and if you have children, contact the European School or local international school well in advance — places fill quickly.
Weeks two to four: meet everyone, ask better questions
Schedule one-on-one introductions with every member of your unit, your head of unit, the HR business partner, the assistant who runs the unit's logistics, and at least three people in adjacent units who work on connected files. These meetings are 30 minutes, social in tone, and the goal is to understand who does what and to be remembered favourably. Ask each person three questions: what's the most important file in your portfolio right now, what's the biggest blocker to making it move, and who else should I speak to. By the end of week four, you should have a working map of the inter-personal landscape around your role — not just the formal org chart.
Read your unit's archived files. Most EU institutions store unit files in shared drives organised by year and by file or dossier. Spend at least two hours per week reading historical correspondence, draft non-papers, and inter-service consultation responses for the dossiers you're inheriting. The political shape of an EU file is encoded in those drafts and revisions; missing it costs you months of context.
Weeks five to eight: take ownership of one specific deliverable
By week five, your head of unit will expect you to own at least one tangible deliverable. Often it's a small slice of a larger file: a specific section of an impact assessment, a standalone briefing for the Commissioner, an inter-service consultation response, a position paper for an inter-institutional negotiation. Take the smallest deliverable you can find and execute it visibly well. EU career trajectories are shaped less by single big swings than by accumulated reputational consistency: officials who deliver clean drafts on time, anticipate political risks, and respect inter-service procedure get trusted with bigger files. Officials who don't, get worked around.
Use your first deliverable as a chance to learn the institution's drafting style. Read three or four examples of the same document type from your unit's archive, copy the structure and tone, then write yours. Submit early and ask for feedback. The feedback you get on the first draft is almost always more important than the deliverable itself.
Weeks nine to twelve: build your network outside the unit
By month three you should be reaching beyond your immediate unit. Three high-leverage networks to develop: counterparts in other DGs or services who work on adjacent files (you'll need them in inter-service consultation), your country's Permanent Representation to the EU (an essential channel for understanding member-state positions), and the trainee or junior officials' community (these are the colleagues you'll work alongside for decades and who will move into senior roles in parallel with you). Take part in your institution's professional and social networks: cross-DG informal lunches, the staff committee, language-learning groups, sports clubs.
If you're a Temporary Agent or Contract Agent, also start thinking strategically about your renewal or career-extension path within the first 90 days. Talk to your head of unit about the formal process, identify the EPSO competitions or CAST Permanent windows that are realistic for your profile, and plan your Assessment Centre preparation timeline backwards from the next likely competition. The internal promotion and renewal process is not automatic; it favours people who plan.
Cultural codes worth learning early
Three cultural patterns differ from most national administrations and most private-sector environments. First, multilingual diplomacy: even if your unit's working language is English, formal documents, meetings, and external interactions often switch to French, German, or another language. Match the language others use. Second, written hierarchy: sensitive communications go in writing, with appropriate copy lists and clearance. Verbal commitments don't survive into the file, and files are how decisions get re-examined. Third, inter-service consultation as a way of life: nothing of substance moves without other DGs and services having a chance to comment. Build relationships with the DGs whose mandates touch yours, and respect their procedural rights even when they slow your timeline.
Set up your professional development from day one
Most institutions offer a generous learning and development budget — language training (often free up to advanced levels), professional certifications, conference attendance, executive education. Identify two or three concrete learning goals for your first year and ask your head of unit to support them in your first formal performance dialogue (typically held within the first three months). Goals that compound: reaching B2+ in a third EU language, completing a relevant professional certification (CIPP for data protection, CFA for finance roles, EU Law diploma for policy generalists), or attending a sectoral conference where your unit has visibility but no presence.
End-of-90-days review
At the end of three months, take an hour with a notebook and answer four questions. Who are the five people most relevant to your work that you've now built a working relationship with? What is the one deliverable you've completed that demonstrates your fit for the role? What three files are you on track to take meaningful ownership of by month six? Where do you need additional skills, languages, or context to operate at the level you'd like? The answers feed your formal probation review and your conversations with your head of unit; they also tell you whether the trajectory you're on is the one you actually want.